In love with my best friend, but she's straight

try talking about it, maybe not directly about you liking her because that's obviously a spooky conversation, but maybe next time she talks about wanting a boyfriend you can jokingly say "what about a girlfriend?" even if it's not really a joke. I think it's cliche advice at this point but I find that communication is the number one thing for both romantic and non romantic relationships, it's not good for you or the connection you have with her to keep your feelings bottled up

Let it go. You can’t change someone’s sexuality. If she ends up liking girls & it’s meant to be then it will happen. Don’t waste your time on a maybe. Life’s too short.