US President Donald Trump shakes hands with DPRK's top leader Kim Jong-un at the Capella Hotel on Sentosa Island in Singapore, June 12, 2018. [Photo/Agencies]

Trump expressed optimism about his upcoming summit with Kim as he tweeted aboard Air Force One: "Heading over to Vietnam for my meeting with Kim Jong-un. Looking forward to a very productive Summit (sic)!"

Before departing for Hanoi, he also said, "We want denuclearization, and I think he'll have a country that will set a lot of records for speed in terms of an economy."

Trump told press on Feb 20 that his trip to Vietnam would be "very successful," anticipating his two-day meeting with Kim would "accomplish a lot."

"That doesn't mean this is going to be the last meeting, because I don't believe it will. But we have subjects to discuss which will be very fruitful," Trump said.

Trump also said on Feb 19 he would like to see the "ultimate denuclearization" of the DPRK, but at the same time noted that he was "in no particular rush" given that the sanctions remain in effect and Pyongyang has refrained from nuclear and missile testing.

Kim Jong-un has instructed officials to make "good technical preparations" for a second DPRK-US summit, the Korean Central News Agency reported on Jan 24.

Kim said that he thinks of Trump in a positive way. With good faith and patience, the two countries will reach the goal step by step.

During his Jan 7-10 trip to China, Kim Jong-un said that Pyongyang will make efforts for the second summit between DPRK and US leaders to achieve results that will be welcomed by the international community. The DPRK leader also thanked China for its efforts.

Kim also said on Jan 1 in his New Year speech the he would push forward the denuclearization and was ready to meet with Trump at any time.