WHY DO I BELIEVE? I believe because I have seen the works of His hands and have heard his voice. I believe in Him because He first believed in me.
BUT HOW DO YOU KNOW HE IS REALLY THERE? I can't be 100% sure but at the end of the day you have to believe in one thing or another. It is more reasonable to have faith in a creator than an explosion that is mathematically impossible. But does it really matter how the world started? I'd rather answer the question of where I will be when it ends.
God needs to be experienced, not understood.