The summit, the first time a sitting USA president meets a North Korean leader, was almost called off just two weeks before the event.
He insisted the United States would accept nothing less than complete denuclearisation.
Another question is whether Trump will take up the issue of human rights - with North Korea accused of a host of state-sanctioned rights abuse including extrajudicial killing, torture and kidnapping.
What did the secretary of state say?
As anticipation for his historic summit with North Korea has ratcheted up, salesman in chief Donald Trump has done something out of character: ratcheted expectations down.
Pompeo says that USA sanctions on the North will remain in place until the North denuclearizes.
Whether they could agree to a draft document will likely determine whether Kim and Trump can sign a tangible "outcome" at the summit. While Trump will be a guest at the Shangri-La Hotel during his stay in the City-State, Kim will be a resident of the St Regis Hotel barely a kilometre away.
Their first meeting will be just the two men, with their translators, without any advisers present.
Mr Trump has said he has a "good feeling" about Tuesday's much-anticipated summit.
Perhaps he'll offer to withdraw the 28,000 American troops stationed in South Korea, Haenle said, or to pull back the so-called nuclear umbrella of protection Washington offers allies South Korea and Japan.
Highly unusually, North Korea's state-run media are already reporting on Mr Kim's trip to Singapore to meet Mr Trump.
The official did not rule out the possibility that additional activities could be added to tomorrow's schedule, beyond the two planned meetings with Kim, ABC News' Jordyn Phelps reports.
Still, even as he turned his attention to the summit, Trump continued his blistering attacks on Canadian Prime Minister Justin Trudeau Monday, saying "Fair Trade is now to be called Fool Trade if it is not Reciprocal".
But analysts who closely watch North Korea believe it is unlikely Kim would have come to Singapore without being confident of the arsenal's security - and the ability to order its use.
For decades the U.S. has been a sworn enemy.
Dynastic descent from Kim Il Sung is the basis for Kim's personal legitimacy - Pyongyang's propaganda promotes the similarities between them in looks, mannerisms and even handwriting.
The summit would discuss "building a permanent and durable peacekeeping mechanism on the Korean Peninsula, the issue of realising denuclearisation of the Korean Peninsula" and other issues "as required by the changed era". Kim is, essentially, upsetting two decades of carefully choreographed North Korean statecraft and stepping into the unknown.
"The underlying driver is a transformational process of Kim Jong-un leading North Korea into a new place in the region and the world", said John Delury, a professor of Chinese studies at Yonsei University in Seoul. Past nuclear deals have crumbled over North Korea's reluctance to open its doors to outsiders.
North Korea's official newspaper Rodong Sinmun proclaimed Kim's arrival in Singapore on its front page, in unusually swift coverage of his global visit.
"I bet the North will not abandon nuclear weapons", he said, adding that the United States and its allies should use both "carrots and sticks" to force the North to do so. He also famously vowed to unleash "fire and fury" if Pyongyang kept threatening the US.
Rodman has developed a relationship with Kim over the years, coming to call him "Marshall".
Kim may also be seeing the gamble in a light never considered by his autocratic father and grandfather because of "his determination to modernize North Korea", according to Ryan Haas, an Asia expert at the John L. Thornton China Center.
Trump is expected to meet Lee on Monday.
What do both sides want?
Denuclearisation has been the central issue in the run-up to the talks.
The North Korean autocrat's every move will be followed by 3,000 journalists up until he shakes hands with Trump.
As the final preparations for the summit were being made, some veteran diplomats warned against an all-or-nothing approach from the U.S.
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