A humble aim
I cannot bring a mind to certainty. Even if you wanted to know one certain thing, upon which everything else could be built, which was actually undeniable – well, I would tell you that the fact of your questioning proves your existence, a la Descartes. But doubt would linger – for your existence, to me, is still not certain in this ironclad way.
Therefore, I do not aim to bring your mind to certainty about God. If your mind should be open to it, then you may reckon with the certainty of your beliefs. Perhaps God will come to your aid.
Now, there have been thinkers who, if given a few simple premises, could draw for you ironclad conclusions. Aristotle, and St. Thomas Aquinas after him, concluded that something like God must exist, based on a few such premises and logic.
To understand that, though, requires some study; the very claim is so shocking to modern minds that one would indeed require a kind of acclimation to their thoughts, their assumptions, and the rigor of their thinking. It says something about our age that such rationality would seem novel, even exotic.
Here again, my aim is humbler. Aquinas may come and advise us, but we are children playing at the game he mastered. Where he was careful, we will inevitably be sloppy. Where he was subtle, we will be rather clumsy.
And yet, it is not for nothing. Such ideas really can take shape, and color, and even life in a conversation like ours. The child, laughing, says something a psychologist might explain; but we prefer the laughter.
I aim for the laughter, for the dim glow of a far-off glory.