With gaps remaining over what denuclearisation would entail, officials from both sides were trying to push the agenda forward ahead of Tuesday's summit.
Trump while meeting Monday with Singapore Prime Minister Lee Hsien Loong, said he thinks the upcoming meeting with Kim will "work out very nicely". "In reality, what we actually get will likely be a more vague statement only pledging to continue to work together", Michael Kugelman, deputy director of the Wilson Center's Asia program, told Newsweek.
There was a sweet ending to the working lunch: an early birthday cake for Trump.
Concrete barricades have been erected outside St Regis Singapore hotel which is within the zoned security area.
"There are only two people that can make decisions of this magnitude". Lee has said the summit would cost Singapore about S$20 million (£11.2 million), more than half of which would go on security.
"We've got a very interesting meeting in particular tomorrow", Trump said at a luncheon with the Singapore prime minister on Monday. Others complained about the traffic jams in downtown Singapore.
The cost of hosting around 2000 global media was put at $S5 million, but Lee said the publicity and boost for Singapore's worldwide standing was worth it.
So just what will a successful meeting between Trump and Kim actually look like? Traffic was held up in the steamy midday sun and scores of bystanders were penned in by police when Trump went to meet Lee. Entry to their hotels is extremely restricted.
Mr Kim's itinerary was reported in detail, which is a rarity for the state's media, according to South Korea's Yonhap news agency. It heralded the summit as part of a "changed era".
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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".
It wasn't immediately clear what specific progress, if any, had been made in preliminary discussions between USA and North Korean officials in the run-up to the Tuesday summit.
Pompeo said the U.S.is prepared to offer "unique" security guarantees to North Korea to ensure that eliminating its nuclear weapons won't end badly for Kim's regime.
Reunification, he said, would be impossible because four powers - the US, China, Russia and Japan - do not want to see a unified Korea.
Why only potentially? That's because these two world leaders are not, strictly speaking, known to be very diplomatic - that is to say that they are in no manner of speaking, known to be very diplomatic at all.
First, the meeting must last longer than a minute.
The other area was Sentosa Island, site of the Capella Hotel which will be the venue for the June 12 summit. And based on the tweets that Trump sent Monday morning, it doesn't seem like he left his baggage from the first summit at the door. Getting Pyongyang to swear off its nuclear ambitions is certainly a central prerequisite and condition of North Korea's impending return to the world order, never mind the summit.
But there are doubts denuclearisation of North Korea is achievable in the short term.