Looking for a manga

Its not Yaoi and is a oneshot, its about a discipline committee couple in school. The chick used to be yankee/delinquent but she fell for the a straight arrow kind of guy, who now is the head of the discipline committee. She is strong and beats the badies at school, but pretends to be a good fragile girl in front of the guy she likes. They go out on a date, where is meets incidents that forces her to show her strength, but somehow is is able to cover it up. Towards the end of their date, they are ambushed by a group of delinquents where she apologises to dude and shows her true strength, he is surprised but blocks a hit coming towards her. In the end they are still a couple. It is also revealed that the guy comes from a infamous yakuza family. In the last panel, it is shown that his father tell the guy when he comes home from the date that a strong girl had saved him (father) on the train from a pervert (this was one of the incidents that happened during their date) and the guy promises his dad to bring her home the next time.

Thanks in advance ε=ε=(ノ≧∇≦)ノ