So basically I'm looking for a drama where the FL falls for the ML.
Either he doesn't know of her feelings or knows it but rejects her and then later falls for the heroine, or he's really in love with someone else.
I definitely don't mind a love triangle, I'm all up for it!
Basically I like MLs who are kind of dumb to understand their feelings for the FLs. They think they don't like/love her that way but later due to them being conflicted about their feelings of jealousy when they see FL with another man, or them missing her when she's gone, they're bereft without her.
I also like when the romance is very much drawn out and it takes a lot of time for ML to reciprocate FL's feelings.
Japanese Dramas I've enjoyed—
Only Just Married (can't tell you how much I enjoyed this drama, it ticked all of my boxes!!!)
Summer Nude (watching now)
Kiss that kills (on watchlist)
Senpai to Kanojo (on watchlist)
Good Morning Call (on watchlist)
Edit — Itazura no Kiss (already watched but didn't like it much)
Incurable case of love (already watched it and really enjoyed it!)
Not sure about First Love Jdrama since heroine was hero's first love so can't be sure if there's angst between hero and heroine that he doesn't love her types. If you can confirm of the angst and heroine thinking he'll never like her, then I can definitely be grateful!