President Donald Trump is convinced that his deal-making powers will give him a unique advantage in the highly anticipated summit with North Korea’s Kim Jong-un on Tuesday.

There is so much that isn’t known about what will happen in the first meeting between a sitting U.S. president and a North Korean leader that Trump tried to lower expectations before he embarked on what he characterized as a “mission of peace.”

Trump recognized there was a possibility Kim wouldn’t be looking to actually make a deal and said he’ll know “within the first minute” if the North Korean leader is serious about nuclear talks. “I think I’ll know pretty quickly whether or not, in my opinion, something positive will happen. And if I think it won’t happen, I’m not going to waste my time. I don’t want to waste his time,” Trump said.

The president is going into the historic summit convinced that he will be able to do complicated geopolitics on the fly. “I have a clear objective, but I have to say—it’s going to be something that will always be spur of the moment,” Trump said. “You don’t know. This has not been done before at this level.” Part of the reason why the National Security Council hasn’t held high-level meetings to come up with a strategy to negotiate with Kim is a “recognition that whatever his briefing papers say, Mr. Trump will act on instinct once he is across the table from Mr. Kim,” notes the New York Times.

Even as he acknowledged there was a “good chance” the meeting would not work out, he also didn’t set the bar for success very high. “At a minimum, I do believe, at least we’ll have met each other,” Trump said, noting that “hopefully, we will have liked each other.” Trump also sent a message to Kim though, trying to make clear that he may not get another similar opportunity in the near future. “It’s a one-time shot and I think it’s going to work out very well,” he said.