How should I respond to the question usually asked by my friends: Do you fancy her?

Let's say I do, if I said yes rumours would spread out (because my friends are such blabber mouths and can't keep secrets!) and she would hear it from someone and I'd get embarred when she finds out. If I said no my friends might flirt with her instead or tell her that I said no ruining my chances of being with her. I'm scared to ignore the question and not let them know because they might treat it as a no and flirt with her. Is there anything I can say other than yes or no that won't cause any problems or embarrments? I'm sure the answer is simple but when you're on the spot you're kind of under pressure, and I want to be prepared, thanks.