"We fell in love", Trump said at the rally.
Trump said Kim sent him "beautiful letters" which brought his guard down during the lengthy peace process.
Even so, the tone of Mr Ri's speech was dramatically different from previous year, when he told the UN General Assembly that targeting the U.S. mainland with North Korea's rockets was inevitable after "Mr Evil President" Trump called Kim a "rocket man" on a suicide mission.
The North, however, doesn't "see any corresponding response" from Washington.
On Wednesday, US Secretary of State Mike Pompeo met with Ri in NY and accepted the North Korean leader's invitation to visit Pyongyang, the State Department said.
Pyongyang has repeatedly appealed for United Nations and U.S. sanctions to be lifted and has support from Russian Federation and China.
"That was a big, big problem", he told his supporters. And they are great letters.
"Without any trust in the USA, there will be no confidence in our national security and, under such circumstances, there is no way we will unilaterally disarm ourselves first", the foreign minister said Saturday. Fast forward to a year and much to everyone's astonishment, Trump was part of a historic summit with Kim in Singapore.
More news: Souness: Milner is a real player compared to selfish PogbaTrump and Kim signed a peace agreement when they met in Singapore in June, but the terms of the accord were vague and lacking substance.
Trump also said that North Korean leader Kim Jong-un was interested in a second meeting. "And we fell in love".
Instead, he noted, the USA is continuing sanctions aimed at keeping up pressure.
The crowd laughed in response to Trump's "love" line, though the comment was more self aggrandizement than humor - he had also just informed supporters that he had prevented the deaths of millions, come up with a better foreign policy toward the rogue nation than President Obama or any other USA leader, and that anyone who says any different is lying.
Instead of addressing the North's concerns about the absence of a peace regime on the Korean Peninsula, Ri said, the USA has insisted that denuclearization come first and increased pressure through sanctions.
However, US Secretary of State Mike Pompeo told the UN Security Council on Thursday that "enforcement of Security Council sanctions must continue vigorously and without fail until we realise the fully, final, verified denuclearisation".
"Past diplomatic attempts to halt North Korea's nuclear and ballistic missile development were unsuccessful", Pompeo said.