President Trump on Saturday expressed optimism about his summit with North Korean leader Kim Jong Un, but warned that the opportunity won’t happen again, calling it a “one-time shot.”

Trump made his remarks in Charlevoix, Canada, at the end of the G-7 summit in a press conference as he prepared to depart for Singapore where he will meet with Kim on Tuesday to discuss issues such as North Korea denuclearization and an end to the Korean War.

Trump expressed hope that the summit would be good for world peace but also for the dictatorship.

“We think North Korea will be a tremendous place in a very short period of time,” he said.

He added that the North Korean government was “working very well” with the U.S. and said: “so far so good.”

"We'll have to see what happens and we're going to know very soon."

The road to the summit has been bumpy, with Trump pulling out of the summit last month after aggressive language from the hermit kingdom.

“You talk about your nuclear capabilities, but ours are so massive and powerful that I pray to God they will never have to be used,” he said in a letter to Kim.

Trump days later announced that the summit was back on but has remained only cautiously optimistic about how the historic meeting would pan out. On Saturday, he told reporters that while he was optimistic, Kim would only get one chance.

“It’s unknown territory in the truest sense, but I really feel confident," he said. "I feel that Kim Jong Un wants to do something great for his people and he has that opportunity and he won't have that opportunity again."

"It’s a one-time shot and I think it's going to work out very well," he said.

At the end of the presser, he said that the minimum he was hoping for was a relationship and a dialogue. When asked how quickly he will know if something good will come of the summit and if Kim was serious, Trump said he’d know very quickly.

“Within the first minute I’ll know,” he said.

As for what issues would be raised at the summit, Trump said everything will be on the table:

“We’re going to raise every issue, every issue will be raised,” he said.