Ok I posted this req here a while ago, but I'll give it another try
I'm looking for an anime or manga (most likely it'll be a manga) that has the protagonist falling in love with his best friend's younger sister and dealing with the consequences (loss of his friend, other awkward moments, etc). I'd greatly prefer it to bet the actual protagonist or another main character, not a side story.
I'll donate you FG as well if you manage to find something I really enjoy
The only thing I've been reced that fit the bill was With!!, but that was very weird (brother's ghost in his sister's body) I'm looking for a more realistic work.