Top 25 Forced/Fake/Arranged Marriages in Korean Dramas

Whenever I see "forced relationship" in a kdrama's synopsis, I just know that I have to watch it.
Forced relationships are type of contracted relationship in which the main leads decide to either get married or be in a pretend romantic relationship. They sometimes sign a contract, other times it's a verbal agreement. There are various reasons that make the characters want to fake a relationship including getting an inheritance, parental pressure, and keeping up appearances. The benefit for audience are forced skin ship, cohabiting hi-jinks, the inevitable falling in love, and perhaps even permanent relationships.
So below mentioned are  top 25 dramas including forced, fake, arranged relationships in Korean Drama:

Full House

Full House is about a writer, Ji Eun, who lives in a house designed by her dead father. One day, she finds out her friends sold her house to a very famous actor, Yeong Jae. She enters a contracted marriage with Yeon Jae and the story starts developing as they gradually fall in love.

Delightful Girl, Choon Hyang

Choon Hyang and Mong Ryong are two high school students that end up spending a night together (nothing happens between them). When their school finds out and in order to save their families' and the school's reputation, they are forced to get married. This drama follows their high school days, their university days and their adult days. 

Goong

The crown prince, Lee Shin, is a high school student who has to marry a common girl, Chae Kyung. This arranged marriage was decided between his dead grandfather and one of his friends. So they get married and Chae Kyung has to move into the palace and follow all the palace’s rules, which have been practically the same since the Joseon period.

Marriage Contract

Kang Hye-soo (Uee) is a single mother who struggles to raise her daughter while paying off her late husband's debts. Han Ji-hoon (Lee Seo-jin) is the son of a chaebol who seeks a contract marriage in order to save his mother, who needs a liver transplant. When Kang is diagnosed with an inoperable brain tumor, she agrees to marry Han and donate part of her liver to his mother, in exchange for enough money to provide for her daughter until she reaches adulthood.

Marriage, Not Dating

A perfect man, Kong Ki-Tae (Yeon Woo-Jin), is forced to marry by his family, but he doesn't to marry. To make his family give up, he introduces a woman, Joo Jang-Mi (Han Groo), to them that they would never accept. 

Fated to Love You

A chaebol heir and a "post-it" girl are forced to marry after their one-night stand results in an unexpected pregnancy.

The King 2 Hearts

The crown-prince of South Korea is forced to work alongside a female North Korean military officer. Political and emotional complications lead to an uneasy marriage engagement. 

Lie to Me

A woman, jealous when her friend steals her first love and marries him, lies that she is married too. The lie ensnares a hotel president who goes along with the lie for his own reasons. Will the lie become reality?

Prime Minister and I

Prime Minister Kwon Yool (Lee Beom-Soo) works well at his office, but he struggles to raise his three children alone. Nam Nam Da-Jung (Yoona) is a reporter full of enthusiasm at work, but she always ends up missing big scoops. Nam Da-Jung comes to Kwon Yool and his three kids like a Christmas present.

Shining Inheritance

A story of restoring the love of a family and the inheritance of a major food corporation.

Mary Stayed Out All Night

It’s about a girl called Mae Ri, whose father lives hiding from debt collectors. Her father’s old friend who recently appeared pays off all the debts and makes an agreement with her father to marry Mae Ri with to son, Jung In. Mae Ri tries to escape this deal by asking Moo Kyul (Geun Suk’s character) to fake a marriage with her.

Sweet 18

Two children are promised to each other by their families, yet lose touch shortly after that and only meet again 18 years later. Despite clashing personalities, they give marriage a shot hoping to make it work and that love will follow.

The Virtual Bride

In-Young is a former idol. She belonged to a popular 4 member girl group, but, now, she isn't very popular anymore. To regain her popularity, In-Young appears on the TV show "Experience of Daughter-in-Law From The Eldest Son's Family." While filming for the TV show, she meets her scripted mother-in-law Yang Choon-Ja. 

Creating Destiny

Sang-eun Han (Eugene) immigrated to Australia at the age of 10. She then went to America and eventually became a lawyer after graduating from law school. Sang-eun tried to marry her boyfriend who is not Korean, but her family was against the idea. Sang-eun then travels back to Korea to persuade her family.

Ho Goo's Love

Ho Goo has never dated in his life. He runs into his first love Do Hee. She is a member of the national swimming team and has a burning desire to win. She also talks like one of the guys. After Ho Goo meets Do Hee again, he becomes involved in a complicated romantic relationship and a dangerous friendship.

Mask

Lee Kang To is an ambitious and callous Korean officer employed by the Japanese colonists. Despite his mother's disapproval of his work and his own brother's antagonistic history with the Japanese, Kang To continues to play by the colonist's rules in hopes of becoming successful and bringing his family out of poverty. However, a mysterious figure wearing a traditional Bridal Mask always seems to get in Kang To's way. An unexpected turn events brings Kang To to cross paths with the mysterious Bridal Mask, changing his future and the nation's history forever.

It’s Okay, Daddy’s Girl

Eun Chae Ryung is a spoiled daughter who had always completely relied on her father. When he is involved in an accident one day, she finds herself rudely awakened from her sheltered life and forced to mature, encountering numerous hardships before she gradually becomes an independent person.

Empire of Gold

Internal strife ensues for two decades as three family members vie for control over a large South Korean conglomerate. 

My Lovely Kim Sam Soon

The misadventures and romantic entanglements of Kim Sam-Soon, a passionate, stubborn, klutzy, and almost thirty year old pastry chef. 

Haeundae Lovers

Prosecutor Lee (Kim Kang-Woo), who lost his memory, becomes involved with gangsters. He then meets Ko So-Ra (Cho Yeo-Jeong), the daughter of a gangster. 

Bride of the Century

In this fairytale-like melodrama, Choi Kang Ji is engaged to an eligible young lady from a small southern island, Doo Rim. But there's one problem: the first bride of the family's first son is always cursed to die.

She is Nineteen

This series is about a 19 year old girl, Yoo Min who was being abandoned after the death of her mother. She lives alone with her adopted brother, Kang Pyo. She accidentally meets Seung Jae, the younger brother of Min Jae. By chance, Yoo Min actually had a crush with Min Jae, a doctor who treats her brother illness for a long time. To fight off his mother demand, Min Jae getsin an engagement contract with Yoo Min and they all end up living at Min Jae's house.

Wonderful Life

Han Seung Wan and Jung Se Jin bumps into each other at the airport and accidentally take each other's passports. They meet again and Seung Wan and Se Jin end up spending the day together. Both having to deal with love complications, they end up drunk and having a one night stand. Back in Korea, Se Jin discovers she is pregnant and leaves to have the baby alone. A year later, SeJin's clueless sister ends up spilling the secret to Seung-Wan at his engagement party, showing up with his baby daughter. Seung-wan and Se Jin are then forced to marry by their respective families. 

1% Of Anything

Kim Jung Hwa is extremely warm-hearted and loves to help other people. When she helps carry an elderly man's belongings from the train to another location, the elderly man is extremely thankful. This grandfather turns out to be the extremely rich owner of a well known conglomerate. His grandson, Kang Dong Won is a quick-tempered businessman who rivals his grandfather, but in an almost comical way. In an order to "tame" his favorite grandson, the grandfather agrees to give his entire fortune to the person who marries Kim Jung Hwa, therefore forcing Kang to meet the girl whom his grandfather chose.

The Accidental Couple

It all starts when actress Ji-su gets involved in a car crash with her secret boyfriend driving the car. Desperate to cover up their relationship, Ji-su drags an innocent bystander, mailman Dong-baek Gu into the car, while her boyfriend flees the scene. The paparazzi then arrives and takes their photos. This brings Dong-baek Gu instant notoriety and things turn more bizarre when he continues to act as Ji-su's boyfriend.

(Source: MyDramaList, Wikipedia)