This is the Difficult part: “Faith” is a Gift of God.
Or, if you ask a philosopher, he might answer that all scientific truths are proven true by the evidence that convinces, through logic, our mind, and we are convinced.
Faith in God, on the other hand, does not have empirical data collected in experiments that can only be explained if a God exists. There is only, at best, a “high probability” or some such vague wording. What there was, for us believers, fortunate enough to believe in God, is a choice, before there is adequate proof, that pushes, forces, or directs our mind, our intellect to simply “accept God”. Period. End of argument.
But, if you ever “fall in love” with another human, you might, or might not, remember that you really, really, had no absolute or logical “reason” to “fall in love” with anyone -or God.
The best argument: Life without Love is dreadful, life without love of God implies life without love for God or love for any of His Creatures. What else is there? Absolute Loneliness? Is that a prelude to madness? Would you ask a madman if he loves anyone? Why?