Kedamono Shounenshoujo

Enatsu is fascinated with cool and aloof Toba. He's rebuffed her 13 times, telling her he hates girls. Enatsu finallly manages to get Toba alone with her and hugs him. To her surprise Toba's personality changes and he almost rapes her. A book falls on his head and he changes back into the Toba she loves. She pretends they went all the way and extorts Toba to be her boyfriend. But what if he finds out nothing happened...?