Someone recently said that this is what they do. (I thought this was brilliant, but it seems like it will only make matters worse)
look at the heckler about to ruin the trick and say "Hey, I'm gonna read your mind. Think of a sentence and I'll write a prediction of what it is."
*Write something on paper and let the spectator, in your case, the girl read it*
She reads what you wrote and it goes like
"Oh the magician (or use your name) has bought a trick and practiced it so well that he is getting so much attention. I am so damn jealous, I know the secret but I haven't practiced so I cannot perform. I think if I reveal the secret maybe she will pay attention to me. I mean I do not really know how to get people to pay attention to me. I guess I will spoil the trick, that will make me look important"
Then go like "So was that what you were thinking?".
I sometimes take it further, when they show the paper they have and it says something else, I go like "Woah dude how did you manage to keep me from reading your mind, guys pay attention to him, he kept me from reading his mind".