The booklet that Mr. Trump sent to Mr. Adelson, who is said to consider the protection of Israel to be among the most important issues in settling on a candidate, featured several photos of the event, including some with him and Ms. Rivers together, according to one person who saw it.

And on the booklet was one of Mr. Trump’s trademark notes, scrawled by hand, according to both people with knowledge of the booklet. Addressed to “Sheldon,” Mr. Trump wrote that “no one will be a bigger friend to Israel than me!” recalled one of the people who saw it.

It was around this time that Mr. Trump spoke to Mr. Adelson by phone, in a conversation that the casino magnate has described to associates as an attempt to secure his support. During that call, according to Mr. Adelson’s recounting of it to his associates, Mr. Trump repeatedly talked about living in a city with a large Jewish population, pointing to his Jewish son-in-law and his now-Jewish daughter…

People close to Mr. Trump have insisted he was more interested in preventing Mr. Adelson from supporting a candidate who could use that money as a weapon against the real estate developer.