Sufism is freedom. It does not create any system around you. It does not tell you to believe in a certain system. Yes, it talks about trust, but not of belief. Trust is a totally different thing. Belief is belief in a theory, in a philosophy, in a world-view:
you believe in Islam, you believe in Hinduism, you believe in Christianity. But when you trust, you trust in life. You don’t believe in life, you trust in life.