It doesn’t really matter if I know God exists, does it? Does it actually change anything? Some atheists claim to know God doesn’t exist...what color do you think they see the sky as, or where the sun comes up?
It matters to me whether or not God exists. The question for you is, “Do YOU want to know if God exists?”
You say you already believe in God, but then say you don’t have a clear idea of “what is truth”, so I ask you, “How do you know God exists with any certainty if you don’t even know what truth is?”