Help I don't know the title

I was reading a manga by the same of Crazy girl shin bia.
The story was about FL who was bullied by ML when they were a child (like me said that she has a wise butt). When they grow they are the leaders of their school and one day they meet again but FL doesn't understand that ML was her bully, so they start to date. At the beginning he is shy but when she found out who he was and what kind of persone he is (like gangster, fighting) ML behaves like the last (but in reality he loves deeply FL) . When FL were kidnapped she decided to dump ML and from here I stopped reading the story.(￣∇￣")