Same as a person of faith trying to prove the existence of God to a non believer. In both cases, ther person doing the convincing isn't sure of themselves, so they need to eliminate the other side. Then they are right.
Makes no sense to me. If believing in God makes you happy and you find strength in it, good for you. If not believing in God does the same, then good for you. Trying to take peace of mind from someone, so you can have it, doesn't work.