I believe President Trump when he says “I never called Meghan Markle ‘nasty.’” I believe him even though Britain’s Sun newspaper published an interview with Trump the day before in which he referred to the Duchess of Sussex with that very word — and even though the Sun has a recording.
Likewise, I believed Trump when he visited Britain last year and said "I didn't criticize the prime minister"— even though the Sun also had a recorded interview of him that time, criticizing Prime Minister Theresa May.
And I am fully prepared to believe Trump tomorrow if he says “I never called Sadiq Khan a ‘stone cold loser’” — even though Trump, landing in Britain on Monday, called the London mayor just that in a tweet that misspelled Khan’s name and also mocked him for being short.