Trump will 'size Kim Jong Un up' in meeting on his commitment to ending nuclear program: John Bolton

National Security Adviser John Bolton said one advantage of President Donald Trump's fast-approaching meeting with North Korean leader Kim Jong Un is that Trump will be able to “size Kim Jong Un up” on his commitment to ending his nuclear program.

“I think what we need to see from Kim Jong Un is that he and the entire North Korean regime have made a strategic decision that they will be better off without weapons of mass destruction,” Bolton told ABC News Chief Global Affairs Correspondent and "This Week" co-anchor Martha Raddatz on Sunday. ““I think one advantage of having this meeting between President Trump and Kim Jong Un so soon, in effect, without months and months and months of preparation, is that President Trump will be able to size Kim Jong Un up and see whether the commitment [to denuclearization] is real."

“I don't think this is a question of psychoanalyzing Kim Jong Un,” Bolton added later in the interview. “I think it's a question of what he's prepared to do concretely and operationally.”

The president announced last week that his summit with Kim will be on June 12 in Singapore.

Bolton said on "This Week," If Kim wants North Korea "to be a normal nation, if he wants to have normal relations with the rest of the world, if he wants trade and investment to be possible for his desperately poor country, this is the path to do it."

The national security adviser emphasized that denuclearization is “absolutely at the core” of the meeting.

“We want to see the denuclearization process so completely underway that it’s irreversible,” Bolton said. “That’s something that has to happen before the benefits start to flow” to North Korea.

That "means getting rid of all the nuclear weapons, dismantling them,” Bolton said. "It means getting rid of the uranium enrichment and plutonium reprocessing capabilities ... It means addressing the ballistic missile issue."

Asked whether that sort of agreement can be reached during the one-day summit, Bolton responded, “I think that we will at least see whether the decision on North Korea’s part to give up nuclear weapons is something that they’re prepared to carry through on, then other discussions could occur.”

“I don’t think anybody believes you’re going to sign the complete ending of the nuclear program in one day,” Bolton added. “But we are also very much interested in operationalizing the commitment as quickly as possible.”

He acknowledged that the administration faces a challenge in realizing its goals with North Korea. He said he doesn’t think the president, whom he said is “optimistic but realistic,” about the chance of a breakthrough, has “stars in his eyes over this.”

"Nobody believes that this is easy to do. It’s going to require some discussion with North Korea, they’re going to have to reveal all of their locations; they’re going to have to allow open inspection," Bolton said.

If North Korea does follow through with full denuclearization, Bolton said, “I think we’re prepared to open to trade and investment with North Korea as soon as we can.”

As to what North Korea could gain from the opening of trade and investment, he referred to aerial photos that show the contrast between the vibrant South Korea and the economically-struggling North. “The South is lit up, you can almost draw the lines of the coastline,” he said. “North Korea, you can't tell the difference between North Korea and the Yellow Sea on the west.”