As is now well-known, Reagan was basically gaga through a good chunk of his second term. People basically knew because of the stories he used to tell. In one of them he described his experiences flying planes in WWII. Except, of course, he never did. What he did was
appear in a film doing that. Another story he told was about how he and Gorbachev were getting nowhere at some summit or other and he suggested that they go off by themselves and talk it out. (This was Camp David, so there was countryside to roam around in.) And, in Reagan's telling of the story, they did. Slight problem: Reagan knew zero Russian, and Gorby knew zero English. I guess they just used very expressive gestures.
I only mention this because...
https://www.nytimes.com/2017/01/25/us/politics/trump-bernhard-langer-voting-fraud.html
(Trump essentially confirmed that he told this story when he bitched to the interviewer (David Muir?) on ABC about how the Dems were rude to leak it. But think how crazy you'd have to be, (a) to believe this story yourself, or (b) to think it would fly in a room full of actual politicians rather than dumb ass-kissing fans at a rally.)