JUNREN

Main character realizes his feelings for childhood friend Yuka, so he enrolls into her school in Tokyo. But Yuka grows very beautiful, and there are serious sempai around her, so protagonist remains just a childhood friend and puts up with the idea that she supposedly already has a boyfriend. Unaware of Yuka feelings, boy confesses to a girl from part-time job, but girl soon realizes that even during dates his heart is elsewhere.
These relations get intricately entangled and gradually change their form...

[From vndbreview]