"Do I believe in God?".
I don't know if you do or not and I still would not know whether you believe in God or not, even if you said that you did believe in God.
Your belief in the existence of God or non-belief in the existence of God or belief in the non-existence of God is irrelevant to every aspect of reality except to you personally, internally and subjectively.
Belief in God certainly does not make God's existence true in any sense. Such belief does not even increase the probability that God exists.