Why do I believe what I believe?
Because if I do not believe, then everything that makes my life full and real and good is dead. Without God, my life is hollow, my feelings mean nothing, and what I percieve as real is not real. I have no hope and no reason for living, but my own pleasure... and I've already tried that and I'm not very happy that way.
I also trust the information provided to me in the gospels... and I'm learning that Buddhists have realized much truth as well. This makes me think there is one truth that we are all capable of discovering... though not through conceptual thought.
I have never experienced a miracle, but I also trust my friends who have described truly supernatural miracles such as God speaking to them or seeing angels and demons. It's not proof, but it helps.