Beyond the speculation over motivation, however, Trump and Kim Jong-un may face huge obstacles to settling a deal on their own; some even question whether a treaty, if they managed to pull it off, could lead to disaster, not peace.
"He's got an opportunity the likes of which very few people have ever had".
"The president has talked tough when it comes to North Korea, but more important than any tweet, more important than any comment about the size of the big red button will be the president's willingness to stand strong and secure a strong and enduring deal", Schumer said.
"We have to get denuclearization, we have to get something going".
In late April, 12 lanky male bodyguards made worldwide headlines after they surrounded Kim Jong Un's Mercedes-Benz vehicle and jogged alongside it whenever the North Korean leader moved across the border.
Mr Trump already has two big wins to show his domestic audience - he welcomed home three United States detainees on their release from North Korea and can show them Pyongyang's destruction of its only nuclear test site.
"I think I'll know pretty quickly whether or not, in my opinion, something positive will happen".
"It's a one-time shot and I think it's going to work out very well", he said.
Trump gave the comments before departing a contentious G7 conference in Canada, during which he confronted top United States allies over trade and drew scrutiny for calling for Russian Federation to be readmitted to the group of nations - and days before his much-anticipated summit with Kim.
When Mr Trump dramatically pulled out of the summit - angered by North Korea calling his vice-president "stupid" - Mr Kim's nearly comically sized letter played a part in the optics of rapprochement.
So why would Trump purposefully say, in front of his friend Abe, who has a lot to lose in the North Korea talks, that he wasn't preparing? "But I can not imagine they'll reach a peace treaty" in Singapore, Hill said.
Historically, North Korea hasn't shied away from signing agreements, but in the implementation of the agreements, things fall apart.
"I think within the first minute, I'll know", Trump said during a free-wheeling press conference before he departed the ongoing G-7 talks for the Singapore summit with Kim. "And if I think it won't happen, I'm not going to waste my time, I'm not going to waste his time".
"The president on Saturday said that he has a "clear objective" heading into the Singapore summit, but that 'it's going to be something that will always be spur of the moment" because Kim has "never been tested".
The 65-year-old wants reunification to be his legacy and was elected in part on the promise of taking South Korea in that direction.
The highly-anticipated meeting between Trump and North Korean leader Kim Kim Jong Un is scheduled for next Tuesday. "People don't know much about him".
Outside the luxury St. Regis hotel, just beyond a busy upscale shopping corridor, construction crews hoisted concrete bollards into place around the perimeter of the five-star complex where the North Korean delegation is expected to stay.
Sporadic provocations by the North have continued while Pyongyang has made increasing advances in its nuclear arsenal, which it says it needs to defend against the risk of a United States invasion. But nothing will be fully settled until China, which sent hundreds of thousands of troops into the North to prevent a quick US victory in 1950, and South Korea also sign off.
The diplomatic initiatives leading to the summit started in late April when Kim met South Korean President Moon Jae-in and the leaders of the rival states pledged to end hostility and establish peace on the Korean peninsula.