Mr. Trump has a long tradition of showing itself to visitors. His office on the 26th floor in the Trump Tower has a window sill with souvenirs, including a championship belt sent to him by boxer Mike Tyson. a football helmet from Tom Brady, the quarterback of the New England Patriots, whom the president once said he hoped would be his son-in-law; and a basketball shoe signed by Shaquille O'Neal, the N.B.A. star.
"This is a serious footing," he told a Wall Street Journal reporter, pointing to the shoe during the 2016 presidential campaign.
What distinguishes Mr. Kim's letters, analysts say, is the key to a highly sensitive diplomatic negotiation on North Korea's nuclear arsenal. They said that the North Korean leader was methodically committed to cultivating Mr. Trump ̵
"We have really built a very good relationship," Mr. Trump said Wednesday, noting that he and Mr. Kim would meet a second time. If he had not been elected, Trump added, the United States and North Korea would be involved in a "beautiful, big, fat war."
"From a negotiation perspective, Trump believes that he has done so by trusting Kim Jong-un," said Joseph Y. Yun, a former State Department official who has negotiated with North Korea.