Must be a manhwa!!!
http://www.mangago.me/read-manga/from_nightmare_to_love/
Maybe it's not that she doesn't believe in love, but she's a little traumatized after her first love.
I prefer stories with fantasy aspects, so if there is something like that, please help me!
Hm... first one that came to mind.
http://www.mangago.me/read-manga/orc_ga_okashite_kurenai/

manhwa about some buff dude and his two-faced high achieving best friend being jealous of him being happy and making a plan to steal his girlfriend away from him