"All I can say is I'm totally prepared to walk away - I did it once before," Mr. Trump said, referring to his move to scrap the June 12 summit, after the North Koreans began making negative noise about their meeting.
Pressed by reporters on what the summit would produce, the President said he was considering the idea of signing a declaration which would officially end the Korean War.
"That could happen, but that's really the beginning," Mr. Trump told reporters in the Rose Garden. "Sounds a little bit strange, but that's probably the easy part. The hard part remains after that."
"Kim Jong Un wants to do something, I think he wants to see something incredible happen for the people of North Korea," the President said alongside the Japanese Prime Minister.
"We shouldn't have waited to this point," Mr. Trump added, gently chiding previous administrations, "but we have a lot of great opportunities."
The President's meeting with Kim Jong Un will begin at 9 pm EDT on Monday, which is 9 am on Tuesday in Singapore.
"I really believe that we have the potential to do something incredible for the world, and it's my honor to be involved," Mr. Trump added.