Hello.
I am looking for mangas in which the girl likes the guy (she tells him or never does. It doesn't matter) but she knows (or actually think/convinces herself) she cant be with him because either he doesn't like her, friendzoned her, already has a girlfriend, likes someone else, sees her as a little/older sister (they do not have to be related for that), etc.
She tries SUPER HARD not to burden him with this feeling, still stays friend with him, cheering for him when he talks about another girl (even if it hurts), does not have any expectation, and even tries to move on with another guy.
BUT THEN, the guy is the one who starts being super interested and wanting her.
Almost like the pattern I mentioned in the title.
A perfect example will be Strobe Edge

Maybe Koiiji? The guy has already married and have a kid but his wife passed away, the girl like the guys since childhood and still loves him now.