Imouto Wa Kanojo Ni Deki Nai No NiImouto wa Kanojo ni Deki Nai no ni; My Little Sister Can’t Be My Girlfriend; 妹はカノジョにできないのに

She has the looks of a model that stands out from the crowd, and on top of that, she has a great personality, too. Daily life with such a sister must seem quite strange to other people.......? This is a romantic comedy about a boy who will "definitely" get together with a cute little sister in the end!(Source: ComicWalker, translated)