Before meeting in Vietnam, Trump demanded North Kora surrender all nuclear weapons- the summit collapsed shortly after.
On December 19, 2003, Libyan Leader Muammar Gaddafi agreed to hand over several tons of uranium from Niger, as well as centrifuge components and the complete destruction of materials from the country's ABC and ballistic weapons programs. The negotiations, held with the Bush administration ahead of the invasion of Iraq, would later become his death sentence.
According to media reports, the denuclearization of Libya and the broken promises that followed with NATO's bombardment in 2011, was the main reason for the North Korean delegation to end the summit in Vietnam. The demands of the United States for North Korea's denuclearization seemed to be too unrealistic to even continue with the joint lunch that was set on the agenda.
The White House so far has refused to respond to the claims. The documents of the summit are considered a secret and are not to be published at this point. However, if true, it would mean that Trump's administration would have to significantly scale down on their expectations towards North Korean denuclearization. Kim Jong Un might think twice if the U.S. can be trusted and he will not repeat the mistakes of Muammar Gaddafi which brought about the total collapse of the Libyan state. It seems more realistic for North Korea to agree to further limit armament, but not to a complete denuclearization which is an insurance policy for the state.
Following the denuclearization agreement with Libya, the U.S. government also asked Gaddafi to speak to his North Korean allies and the Islamic Republic of Iran, hoping he could influence the demilitarization of both countries. Gaddafi's son, Saif al-islam, also stated in an interview, that the United States offered Libya security guarantees. However, any such guarantees were broken when NATO began its bombing campaign during the so called Arab Spring in the country. Much of it based on lies.