It is my theory that all proofs of God break down into either "circular reasoning" or "argument from ignorance".
Your argument is:
P1: God is truth.
P2: Truth exists.
C: Therefore, God exists.
P1 assumes God exists, then is used to prove God exists. A classic example of circular reasoning.
Now, if you want to define God as being a synonym for "truth", that is fine. In that case, I'll go along. BUT, you better not give God any characteristics that the word truth does not have.
It is the God that I had a burger for lunch today.
"Do you swear to tell the God, the whole God, and nothing but the God, so help you truth?"