Ok, so A) I didn't quite understand that and
B) Find out who she is. And then decide how much you value you're friendship with her. If you would like to pursue a relationship with her further, then go ahead. If you don't want to risk losing her as a friend, tell her this
"Okay, (insert name here), I do like you. But, I like being just your friend. Not that I wouldn't want to go out with you, but I don't want to risk losing you as a friend. I don't want things to be awkward between us. So just because I don't want to go out with you doesn't mean I don't like you. It's the fact that I like you that I don't want to go out with you...If you understand that."
You can add you're own little flare in there. And if you don't know her than go ahead and decide if you like her or not and go out with her or not. And if it works out, invite me to the wedding lol.