You can prove that God exists for two reasons: 1) It is a formal result in the method of inquiry called metaphysics. 2) People who don’t admit that God exists are either ignorant of the proof, don’t understand the proof, or are being disingenuous. A possible example of disingenuousness is the “Who made God?” argument. Many people don’t understand why humans are embodied spirits.
If everyone knew and understood the proof and some made the judgment that God exists and others did not, then the proof would be just an argument. Saying someone who disagrees with you has bad judgment or is irrational is circular reasoning.
Faith in God is a positive response to revelation. It is both a decision and a gift from God. If someone says, “God hasn’t given me the gift of faith,” they are admitting God exists and are acknowledging the persuasiveness of the reasons to believe. It is wrong to criticize the judgment of people who don’t agree that God has communicated Himself to mankind.