Whenever Trump opens his mouth there is a 98% chance that a lie will come out. It is amazing that the press will spend hours asking questions all the while knowing that his words will not stand up to fact checking.
The Press should let Trump answer any question with whatever retort his little brain comes up with but they should always follow up with the following question.
“Are you willing to repeat that under oath?”
That is all they have to ask him. If he is not willing to state that under oath that confirms he is lying. If he is willing to say it under oath then subpoena his ass. If he does not show up it means he is again lying about being willing to testify under oath,