Koikimo.

One rainy day, salaryman Amakusa Ryo is saved by a high school girl he doesn't know at the station. He later finds out that the girl is Arima Ichika. Ryo is somewhat of a womanizer and to repay her for saving him, he suggests giving her a kiss or going out on a date with her, in which Ichika tells him he's creepy. This, however, opens a new door for Ryo and he falls madly in love with her. Ever since then, Ryo tries to overly express his feelings to Ichika. Ichika just keeps insulting him and says he's being creepy, but he just seems to take it as her way of showing affection towards him...