"North Korea, under the leadership of Kim Jong-un, will become a great Economic Powerhouse".
Mr. Trump confirmed he was meeting with Kim on February 27 and 28 during his State of the Union address this week.
The US wants North Korea to make a full declaration of all its nuclear weapons facilities and commit to destroying them, under worldwide supervision - something North Korea has never said it will do.
Some in South Korea hope that Kim will be ready to make meaningful concessions in Vietnam that Trump could then respond to by partially easing the sanctions on the North to allow more inter-Korean cooperation.
South Korea's Ministry of Foreign Affairs (MOFA) announced late Friday that Biegun would hold talks with foreign minister Kang Kyung-wha and his ROK counterpart Lee Do-hoon starting at 1000 local time Saturday.
Communist-ruled Vietnam, which has good relations with both the USA and NKorea, has been keen to host the 2nd Summit as a demonstration of its normalization of ties with the United States since the Vietnam War, which ended in Y 1975 and killed more than 58,000 Americans and an estimated 3-M Vietnamese.
Mr Trump said his representatives had a "productive meeting" and that he was looking forward to advancing peace.
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He called the press conference an opportunity "for him to resign gracefully and we are disappointed that he didn't do that". He said if he had posed for that picture, "I would have remembered that". "Ralph, back then and even now, is not a racist".
USA and North Korean flags are on display for sale at a flag shop in Hanoi, Vietnam.
On Thursday, Trump's special envoy for North Korea, Stephen Biegun, held a second day of talks with officials in Pyongyang, North Korea's capital, to hammer out summit logistics and an agenda.
Both sides said they were committed to denuclearisation, but with no details of how this would be carried out or verified.
Biegun said in his speech that the United States had told North Korea it was prepared to pursue commitments made in Singapore "simultaneously and in parallel", and that Washington is willing to discuss "many actions" to improve ties and entice Pyongyang to give up its nuclear weapons.
In announcing the location of their second meeting, Trump showered praise on Kim, whom he used to derisively call "Little Rocket Man". But progress has since stalled, with the two sides disagreeing over what that means.
There's also speculation about a possible four-way meeting, also including Moon and Chinese President Xi Jinping, to declare a formal end to the Korean War, which stopped with an armistice and left the peninsula still technically at war. "President is very much looking forward to taking next steps".