Someone needs our help!

A girl has been friends with [Joe] for quite a few years. Then, Joe came out and told her that he really likes her, like more than a friend! But, our girl doesn't have feelings for Joe, but she feels that she might be sending the wrong signals to this guy. I.E. she doesn't like him, but she thinks she's telling him she does. Her question for us is:

Can you guys give me some advice on how to not send wrong signal?

Let's give her our best advice, guys!
~King~

End