It is like when you saw a coin in my hand and I close my hand to cover it and ask you “Do you believe that there is a coin in my hand?” the answer would be no I don’t believe that there is a coin in your hand, I KNOW that there is a coin in your hand.
In terms of my faith, my concept of that is also like the coin. Even though I don’t personally see God in the flesh, I KNOW that he is real, I KNOW that he is here with us. I feel his presence everywhere I go, he’s in my heart and in my mind.
I don’t believe that God exist, I KNOW that God exist.