Are you genuinely asking for advice? If so try talking to her first, she obviously thinks you’re more than just friends, just tell her you are happy having her as a friend, and although you care about her you dont see her as anything more than a friend.
If that fails and she doesn’t get the nice approach u might have to be a bit mean, I’ve been in that situation before and found talking about another other person I like and fancy to the “friend” works, it will hurt her but she should get that u dont want a relationship with her!