Films or dramas about unrequited love getting reciprocated?

Do you know any films or dramas about unrequited love getting reciprocated? Preferably Japanese or Korean. No comedy, youth, or school-age recommendations, please. Prefer something serious and mature.

Roppongi class

It doesn't matter if ML or FL has unrequited love.

Descendants of the Sun, FL shuts down ML immediately, as their outlooks on life differ greatly (action/medical show)

You Are My Destiny, ML is in love with 2FL (this has some comedy, but it is hard-on unrequited, painful love for most of the drama; and who can resist Jang Hyuk and Jang Na Ra acting together?)

My Dearest, FL is in love with 2ML (historical show)

Itaewon Class, ML has autistic tendencies and believes he is in love with someone who earned his respect, 2FL (revenge show)

Happiness, ML is in love with the FL (zombie show)

When the Phone Rings, ML is in love with the FL (thriller show)