Jon quickly looked around. Everything seemed okay, which didn't mean it was. "Er, what is your hearts' desire?" he asked his half-girl friend. He hoped it was something safe, like living forever, or peace on Earth (which wouldn't even do anything given the stone's range).
"Huh?"
"Fine. I wish you'd tell me what your hearts' desire was when I made that accidental wish, then forget that you told me and forget about the stone and its wishes."
There was another flash as Jon put the stone away.