Forgetting that he was holding the stone, Jon said "I wish you were attracted to me, not some girl." Jon had grown up with Karyn. They were childhood friends. But recently, their relationship had grown, at least in Jon's eyes. He had a crush on her. And he was building up enough confidence to ask her out.
But now, after he found out that she was a lesbian, all of that fell away. As a lesbian she would never go out with him. Fortunately, Jon had the stone. And with it, he could make things the way he wanted them to be.
After Jon made his wish, the stone glowed, granting it.
