Any K or C dramas, where the female lead wants to kill the male lead.. and during the process she falls in love with him. Like The Legends (2019) w/ Bai Lu . 

Please the drama most not be that dark. 

Maybe Cruel City (not kill per say, and can't actually remember much but loads of people like it)

Goodbye My Princess (Falls in love, then wants to kill him but can't because she loves him)

Sword and Flower- Have not watched.

**Hwayugi is literally what you want but its ML killing FL.

Sorry I can't really think of anything that literally fit the bill, anyone else??

THE KINGS WOMAN

CRUEL CITY 

Not sure how dark is dark for you, but you might like Empress Ki - it's a historical drama and it does get pretty dark