Saying that you don't stand for your believes is a logical fallacy. You see the mere fact that you're saying this is enough proof that there's something that you belief and stand for at other people's attacks.
Now if it's refered to an specifical class of belief then I should say that I don't know, I must be in an extreme situation to see if I'm capable of defendinf it. But I'm pretty headstrong, not good, but just who I'm.