In my opinion the only thing that i can be 100% certain of is " I am"
I am therefore of the opinion that whilst a Christian can't prove God exists, and neither do I believe that they can explain the trinity succinctly, this doesn't mean that God doesnt exist, and I accept as a satisfactory answer "I know"
My personal viewpoint may be different but I accept someone saying " I know" as a satisfactory answer, because I can't offer conclusive proof they are wrong.
The Rebel.