Every person knows that Christ exists and they know that God is the Creator. Some are willingly ignorant. They do mental gymnastics to hide the truth from themselves. This is accomplished through confirmation bias.
If you meet such a person, here are some things that you can tell them. These things are universally true of all who take the skeptical approach to Christ.
Christ is offering you freedom from your sin today. You are rejecting this freedom.
You have presented no evidence that conclusively proves that I am not experiencing what I am experiencing with Christ.
You have presented no evidence that conclusively proves that everyone who seeks Christ in sincerity, humility, and respect does not find Him.
You have presented no evidence that conclusively proves that everyone who follows Christ is not led by Him.
You have presented no evidence that conclusively proves that assumptions such as materialism/atheism, naturalism/atheism, and uniformitarianism/no-floodism ought to be taken as axioms of science.
You have presented no evidence that proves scientism.
You have presented no evidence that conclusively proves that God doesn’t exist.
You have presented no evidence that conclusively proves that God does not speak through the Bible.
You have presented no evidence that conclusively proves that the Bible is not God-breathed both when it was written and whenever it is read or brought to mind.
You have presented no evidence that conclusively proves that the Bible is not the Word of God without error.
You have presented no evidence that conclusively proves that creation and the flood didn’t happen using science or any other means other than stories, assumptions, lies, and irrationality.
You have presented no evidence that conclusively proves that God has not made Himself known to you through the creation–every other explanation for the creation breaks known scientific laws that must be rationalized away.
You have presented no evidence that conclusively proves that the molecules-to-man evolutionism story every happened or is even possible–though, I am aware that there are some very creative stories about how there might be ways around the various scientific laws that it violates.
You have persented no evidence that conclusively proves that the old-Earth-ism/old-Universe-ism stories.
You have presented no evidence that conclusively proves that the Genesis flood did not take place.
You have presented no evidence that conclusively proves that Atheism has anything to do with reality.
My experience is that all so-called evidences for such things are based on made-up stories, arbitrary assumptions, irrational thinking, or outright lies. Can you present any evidence at all without resorting to flimflam?
So, you can understand why I think that it’s arrogant of you to press the issue without any evidence.
And, you can understand why I choose to believe Jesus Christ as I’m learning to be led by Him moment-by-moment and learning to respond in obedience. He has provided wonderful evidence to me that contradicts all of the things that you, without any convincing evidence, claim. Why should I, or anyone else, believe you?
Since you persist in refusing to acknowledge God, there is no sense in discussing this further. You seem to be closed-minded to Truth and open-minded to lies in your willing ignorance and will have to face your Creator having heard the Good News of your redemption and having rejected God and His ways with your eyes open. Yet be sure of this: The Kingdom of God has come near to you today.