Here's the principle...
If you want it to stick, it has to be true.
I am not aware of any evidence that Trump ever went to a prostitute. Nor am I aware that Melania married Trump for money. So, you can certainly say those two things, but I don't believe they will gain currency.
Or does it only work in one direction?
Always works in every direction, when it contains truth. It historically marks the zenith of popularity, when people begin to make fun of the person, their symbols, etc.
Witness the turning on Obama.
“If you want it to stick, it has to be true. “
Trump has admitted sleeping with other men’s wives. What would you call that?