HANOI, Feb 27 - U.S. President Donald Trump and North Korean leader Kim Jong Un meet on Wednesday for their second summit, betting their personal relationship can break a stalemate over the North's nuclear weapons and end more than 70 years of hostility.

Despite little progress toward his stated goal of ridding North Korea of its nuclear weapons since first meeting Kim in Singapore last year,Trump has said he is fully committed to his personal diplomacy with Kim.

Trump said late last year he and Kim "fell in love", and on the eve of his departure for the second summit said they had developed "a very, very good relationship".

Whether the bonhomie can move them beyond summit pageantry to substantive progress on eliminating Pyongyang's nuclear arsenal that threatens the United States is the question that will dominate their talks in the Vietnamese capital of Hanoi.

"Vietnam is thriving like few places on earth. North Korea would be the same, and very quickly, if it would denuclearize," Trump said on Twitter.

"The potential is AWESOME, a great opportunity, like almost none other in history, for my friend Kim Jong Un. We will know fairly soon - Very Interesting!"

Trump and Kim will meet at the Metropole hotel at 6:30 p.m. (1130 GMT) on Wednesday for a 20-minute, one-on-one chat followed by a dinner with aides, the White House said.

The elegant interior of the 118-year-old Metropole thronged with security personnel and hotel staff as final preparations were made.

On Thursday, the two leaders will hold "a series of back and forth" meetings, the White House said. The venue for those meetings has not been announced.

In Singapore, they pledged to work toward denuclearisation and permanent peace on the Korean peninsula. North and South Korea have been technically still at war since their 1950-53 conflict, with the Americans backing the South, ended in a truce, not a treaty.

The Singapore meeting - the first between a sitting U.S. president and a North Korean leader - ended with great fanfare but little substance over how to dismantle North Korea's nuclear weapons and ballistic missiles.

Both sides are likely to feel pressure to agree on specific measures this time - what concrete steps North Korea will take to give up weapons that threaten the U.S. mainland, and what the United States will offer in return.

Many analysts believe North Korea won't commit to significant disarmament unless punishing U.S.-led economic sanctions are eased.

Trump has held out the prospect of easing them if North Korea does something "meaningful".

Concession?

In the run-up to the summit, Trump has indicated a more flexible stance, saying he is in no rush to secure North Korea's denuclearisation.

The two sides have discussed specific and verifiable denuclearisation measures, such as allowing inspectors to observe the dismantlement of North Korea's Yongbyon nuclear reactor, U.S. and South Korean officials say.

U.S. concessions could include opening liaison offices or declaring an end to the technical state of war, they say.

Vietnam, relishing its role as mediator, could serve as a model for North Korea.

Vietnam normalised ties with old battlefield foe the United States in 1995 after decades of Cold War mistrust, and its "Doi Moi" reforms transformed its economy.

Trump is due to meet Vietnam's president, Nguyen Phu Trong, at the grand presidential palace, before he meets Kim.