Considering Trump’s career and its success it is highly unlikely he ever used that word anywhere, public or private.
Yeah, we used to use it all the time in prison, but, we were dealing with rap artists and Eddy Murphy wanabees.
But you're right. Until I hear definitive proof that the word was uttered even once by him, I'm leaning towards never .. in his adult life. And if he ever said it as a youth, I'd wager his father would've set him straight.