We are part of God and God is part of us. We are in God and God is in us. If you look for God where God is, not where God is not, you will find him, and know, not just believe, that God exists. And, what’s more, when you really know that God exists, you will have even more certainty that you exist, and that you are far more than you now believe yourself to be. After all, we are all Gods.
When you really come to know this, you will no longer feel the need to go church-shopping, in order to bolster your own weak beliefs by trying to find somebody else who agrees with you. Instead, you will seek the fellowship of like-minded individuals. At this point, the existence of God, the existence of an after-life, and the existence of parallel planes of existence will, in your mind, be answers, not questions.