Trump is a narcissistic sociopath and a compulsive liar; they NEVER admit to ANY wrongdoing, or to lying. What you have to do is present them with undeniable, factual truth, from which there is no escape, no weaseling out of. Then and ONLY then do you get the REAL truth; you have to craft a trap from which there is no escape possible.
I have worked with a few of these types of people and though they might not be the sharpest tools in the shed, they ARE incredibly adept at slithering out of admitting that they lied.
Trump will have to have at least 2 people drop the dime on him and tell the truth, before he’s left with no option but to try and explain himself.