“Do you believe in God,” Yes, I do, because I have met Him. I believe in His existence just like I would believe in the existence of every other person I’ve met. He entered my soul and revealed Himself to me, so that I not only believe He exists, I know (imperfectly, but truly) who He is.
Yes, because I am made in His image, and so have an innate knowledge of Him.
Yes, because He is revealed in the design of ourselves and all creation. We all testify of Him by our very existence. Life does not create itself.
So many philosophy courses teach abstract sort of ways of belief, yet, belief in Jesus is personal, because He is a person who knows you who you can also know.
“Is there any possibility that God does not exist?”
No.