The Singapore summit between the United States and North Korea is a "one-time shot" and a "mission of peace," President Donald Trump said Saturday.

Trump and North Korea leader Kim Jong Un are slated to meet in person in Singapore on Monday night ET. The U.S. wants North Korea to give up its nuclear weapons permanently.

Trump says he's confidant "something positive will happen" at the summit. An official deal between the countries is largely unexpected.

"I feel that Kim Jong Un wants to do something great for his people, and he has that opportunity," Trump said. "And it's never going to be there again."

Trump also noted, as he spoke at the G-7 conference in Quebec, Canada, that he will know "within a minute" whether Kim is serious about giving up his country's nuclear program. "It's my touch, it's my feel. It's what I do."

"This is unknown territory in the truest sense. But I feel really confident," Trump told reporters. "It's never been done, It's never been tested. So we are going in with a really positive spirit."

The summit will mark the first time that a sitting U.S. president and a North Korean leader have met.