"Sometimes you have to walk," Trump told reporters after two days of meeting with Kim, but he said he hoped that U.S. and North Korean negotiators would keep talking.

Trump said he was not willing to accept Kim's demand that the United States end all economic sanctions on North Korea before it committed to a specific denuclearization plan.

"It was about the sanctions," he said. "We couldn't give up all the sanctions" 

Despite the impasse, Trump continued to praise Kim, calling him "quite a guy and quite a character," and saying that there still was a lot of "warmth" in his relationship with a man many regard as a brutal dictator.
Defends Kim on Warmbier
Trump also defended Kim over the death of U.S. college student Otto Warmbier, who died after suffering a massive brain injury while in a North Korean prison.

"I don't believe he knew about it," Trump said of Kim.

The announcement of the collapse Trump's talks with Kim came after the two tamped down expectations for the two-day summit that played out amid ceremony in Vietnam and political turmoil for Trump back in the United States.

Just a few hours before cutting off the talks, Trump predicted that the two leaders would "ultimately have a deal" but said that "doesn’t mean we’re doing it in one day, in one meeting." He again praised Kim for not conducting weapons and missile tests since their first summit in June in Singapore.

Trump had spoken guardedly throughout a morning of meetings with Kim that came just after his former lawyer, Michael Cohen, implicated him in criminal wrongdoing back in the United States.

Kim, taking the unprecedented step of answering a western reporter's question, said "it's too early to say" whether there will be a deal, but "I would not say I’m pessimistic.”

Later, again responding to an American reporter, Kim said he is willing to denuclearize his nation's weapons systems. "If I'm not willing to do that," he said, "I won't be here right now."

"That might be the best answer you’ve ever heard," Trump chimed in.

Little more than an hour later, the White House announced the summit was ending early.

In 2016, the North Koreans detained Warmbier, a University of Virginia student, accusing him of trying to steal a propaganda poster, and sentenced him to 15 years of hard labor without trial. 

A year and a half later, he was returned home to his parents in Cincinnati with a massive brain injury that left him blind, deaf and unable to move on his own. He died a few days later.

At a news conference after the Hanoi summit, Trump was asked by a reporter about whether he pressed Kim on the Warmbier case.

"He tells me that he didn't know about it and I will take him at his word," Trump said.

'Program change'
It turned out that the leaders could not bridge the U.S. demand that North Korea provide a specific plan for denuclearization and North Korea's demand that the U.S. end economic sanctions first.

The first word of the impasse came as reporters gathered for a photo opportunity at a Trump-Kim lunch of snow fish and apple foie gras jelly. As the room sat empty, a White House aide came in and announced there had been a "program change."

Trump described the talks as a very productive two days

He said Kim “has a certain vision and it’s not exactly our vision” on denuclearization”.
He said Kim wanted all sanctions lifted, which the United States could not agree to.
Trump said Kim promised him “he’s not going to do testing” of rockets and missiles or anything nuclear.
He said dismantling the Yongbyon nuclear complex was discussed in exchange for lifting of sanctions.
Trump described China and Russia as having been helpful in the process.
No commitment yet to a third summit, but hopes next meeting could be soon.