The unraveling of the Canada summit meeting increases the North Korean leader's incentive to "up his asks and limit his compromises and for Trump to do the opposite", Richard Haass, the president of the Council on Foreign Relations, said on Twitter, adding, "Hardly the ideal context".
During a post-lunch stroll through the gardens of the Singapore hotel where the summit was held, Trump said the meeting had gone "better than anybody could have expected".
Hatred of the United States can often seem like an integral part of North Korean life, along with loyalty to the Kim family and support for the country's nuclear program.
On the day before the meeting, weeks of preparation appeared to pick up in pace, with USA and North Korean officials meeting throughout Monday at a Singapore hotel.
Historic meetings between the U.S. and North Korea have advanced so rapidly that Donald Trump will leave Singapore earlier than expected.
Larry Kudlow, the White House senior economic adviser, CNN on Sunday Trump is "not going to let a Canadian prime minister push him around" in advance of the North Korean meeting.
Sung Kim, a US diplomat, appears at a hotel in Singapore for working-level talks with North Korean officials on June 11, 2018.
"Meeting in Singapore with North Korea (the DPRK) will hopefully be the start of something big ..."
Trump spoke only briefly in public on Monday, forecasting a "nice" outcome.
Trump "is an incredibly instinctive, intuitive, off-the-cuff, winging-it negotiator", said Marty Latz, the author of the forthcoming book "The Real Trump Deal." "He just goes and he does it".
China and South Korea would have to sign off on any legal treaty. If that's the approach Trump is instinctively drawn to, U.S. officials and experts worry Trump could make the concession in his first meeting with Kim.
Inside, they sat alongside each other against a backdrop of North Korean and USA flags, with Kim beaming broadly as the United States president gave him a thumbs up.
North Koreans gathered outside a train station in the capital, Pyongyang, to watch news of the summit broadcast on a large screen.
Analysts will be closely scrutinizing the two men's body language - physical contact, facial expressions and more - as they meet for the first time in front of the Capella Hotel. The U.S. president turns 72 on June 14. And how will Trump react if he does?
Many experts on North Korea, one of the most insular and unpredictable countries in the world, remain sceptical Kim will ever completely abandon nuclear weapons.
"People are going to be very impressed and people are going to be very happy and we are going to take care of a very risky problem for the world", Trump said.
Most ordinary North Koreans rely on a monotonous diet of rice, corn, kimchi and bean paste, and they lack essential fats and protein, according to testimonies from defectors and from United Nations officials allowed to visit. Tuesday's meeting could pave the way toward a "new era of prosperity, security and peace", Trump said.
As Trump sought to build a bridge with Kim, he was smashing longtime alliances with Western allies with his abrasive performance at the G-7 and angry tweets directed at Trudeau and sent from aboard Air Force One as Trump flew from Quebec to Singapore.