Check out these amazing Relationship themed Asian films - AsianFilmFans

Minato (Nana Mori) is a university student and has a fear of germs. She isn't interested in looking pretty. She lives with her stepbrother Toru (Hokuto Matsumura), who is her stepbrother from her mother's remarriage. Meanwhile, Toru is handsome and a player with the ladies. He doesn't resist women who come on to him and he doesn't stop women from leaving him either. Minato is uncomfortable with Toru and his ways with women. They are the same age and attend the same university. They have an agreement, where Toru will not approach Minato within 2 meters when they are outside. One day, due to her friend’s request, Minato puts on make-up and wears her friend’s high school uniform. While she is out walking in public, she happens to meet Toru. She unexpectedly lies to him about her identity and tells him that she is a high school student. Toru falls in love with her at first sight. --asianwiki

Liar x Liar (2000)

Desperate to go to the U.S. to win back his girlfriend, Yim hires a tutor to teach him English. But things don't go according to plan.

I Fine... Thank You... Love You (2014)

Wing is a devoted fan of popular singer Rose who is involved in a topsy-turvy relationship with her charismatic producer Sam. Willing to go to any length to meet Rose, the willowy Wing disguises herself as a man, and with a twist of fate is chosen to be the next budding star for the record company.

He's a Woman, She's a Man (1994)

Born into a wealthy family, Xiao-wei lives a carefree life with his loving mother's care. He enjoys reading picture books written by his favorite author Kauff, especially those works about mermaids. One day, he accidentally takes the wrong bus, arrives at the seacoast and meets a mermaid, Blue. He believes Blue is the embodiment of the character in those picture books. Since then, Xiao-wei's "normal life," has become not "normal."

A Fool in Love, Love Like a Fool (2019)

Music producer Sam and his cross-dressing protege Wing have finally professed their love for another, but now what?

Who's the Man, Who's the Woman (1996)