Osoraku Kanojo wa Ore no Aniki o Neratteru

Synopsis

A high school guy who doesn't trust girls anymore has been tricked too many times by girls who just wanted to get close to his good-looking older brother. After all that, he decides he’ll never trust a girl again. But then, a pretty girl in his class suddenly starts talking to him a lot. Is she just trying to get to his brother too…? Or does she actually mean something else? (Source: Manga Park, translated)