Goong (2006)

Its is the Thai remake of Goong with nice scenaries,landscapes and ofcourse since the remake was made in 2017 more bright and clear videos

Both have the main couple entering into a marriage against their will. The female lead in both agrees for family reasons
(to save her father's house in Full house while to save her family from loan sharks in Goong). Also, the male lead still loves his ex at the time in both.
What starts out as an unwilling relationship turns into love- with teasing, arguing, jealousy along the way.

Modern day monarchy! Great chemistry between the cast members. The plot was so interesting and Lee Seung-Gi is in it!

Both are Korean dramas about an ordinary girl becoming a princess and learning that life as royalty is not all glitz and glam. Also both dramas have a romantic theme of hate turning into love.

Both girls can be lovingly called monsters ;)

Both are: nice and poor girl has to marry an arrogant, mean and rich guy who is already in love with another girl.

-Poor Female Leads
-Rich Male Leads in a position of power
-Contract Romance and Marriage
-Cohabitation
-Male Lead has girlfriend in the beginning that the Female Lead "ruins" by events out of anyones control
-Sweet Second Male Lead
-The Second Female Lead and First Male Lead try to continue a relationship before guilt for the Female Lead gets in the way for the Male Lead
-Annoying Time Jump

both dramas feature an old, historic and conservative family that has to face a lively (future) daughter in law.
While the FL has to adapt to her new family, the family is changing because of her.
Similar is also the drama sweet 18 (https://mydramalist.com/294-sweet-18)

In both series the main characters need to marry because of an old betrothal made by their grandparents.

There are somewhat F4 in Goong, and they have a similar feeling.

These two dramas have almost identical plots and they are also based on manhwa.

Both dramas hold beautiful and funny moments. Usually the girl lead brings big laughters and each time pisses off the male lead, but as they encounter each other every day and time passed by, they fall in love. The plot will move you from happiness, to a bit melodramatic. If you're watching either one and loved it, you'd definitely love this too!

Both have their marriage arranged by their grandfathers, he is rich and famous and She is just a commoner.

Both are very fun to watch, have that loud and quirky heroine and in contrast the cold, quite hero (well the guy in my girl isnt that mean, but you know...!)And of coarse there is the pitiful second guy who is absolutely obsessed with the girl, but she cant help but be in love with the mean guy. And both feature the ex girlfriends that you wanna murder.

Both series involve a young, naive, and silly girl forced into a marriage with a serious, cold guy. She then has to learn to behave in a certain way as she is thrust into the public spotlight. In Goong, the guy is the crown prince while in Prime Minister and I he is the Prime Minister.