ML wants to Kill FL

yeah thats it pretty much

1. ml wants to kill fl (could be of various reasons. like historical drama, he was ordered to assassinate . modern drama fl affected his life drastically, killed someone close to him thus he wants revenge etc etc)

2. fl isn't an idiot who can be killed. strong fl.

3. cat fight i guess?

anything like this? any language will do

KLeun Cheewit - kinda is this. She killed his fiancé now he is out for blood. more or less. 

The killer is also romantic - historical mr. & mrs. smith, both leads at a point fight with each other but on next day their bed was broken due to intense love-making lol.