W-Pinch!! 

Timid and shy Kawai Arisa is a normal 14 year old High School girl, except that she is the target of bullies as her family tend to move around a lot due to her parents work. The fact that the Prince of her class, Inogami Yuuki, is the only person who's nice to her, makes another reason for them to pick on her. One day new transfer student Yashiro Akira accuses Arisa of bullying him when she lived in his hometown, but the thing is Arisa has no memory of her life before she fell down the stairs five years ago! Could the timid Arisa really be the tyrant ARISA of the past? Is there such a thing as split personality? What other "memories" will come to trouble her.