Sanders and Trump's lawyer are both speaking on behalf of the president. If the first was a lie, Donald Trump could have easily done what he always does when contradicting his staff and tweet the true story. If the second, he could have done the same. There are only two theories that would mean he was telling the truth. One is if he was being held hostage and they were releasing the statements on his behalf. And monitoring what he was writing on Twitter so he couldn't leak it. The other theory would be that every single news network that broadcasted Sanders public statement bribed the members of the crowd to keep silent as to the contents of the speech, then digitally manipulated her voice and mouth to make it look and sound like she was saying one thing when she was saying the other. And the station that held the interview with the lawyer had a gun trained on the lawyer. After the interview was aired, the lawyer would have to be monitored to make sure he didn't come out and say the truth. Oh, and everyone in the White House is either a hostage or in on it.
Those theories...no, they're not true. So Donald Trump is lying.