HANOI/ABOARD AIR FORCE ONE- U.S. President Donald Trump headed for Vietnam on Monday for a second summit with Kim Jong Un, having stressed the benefits to Pyongyang if the North Korean leader gives up his nuclear weapons, but saying there was no rush.Trump and Kim are due to meet in the Vietnamese capital, Hanoi, on Wednesday and Thursday, eight months after their historic summit in Singapore, the first between a sitting U.S. president and a North Korean leader.While there is no real expectation that the second meeting will bring a final deal on ridding North Korea of nuclear weapons that threaten the United States, there are some hopes it could bring a declaration that the 1950-53 Korean War is at last formally over.In Singapore, Kim pledged to work toward complete denuclearization of the Korean peninsula, but the vague agreement struck there has produced few concrete results. U.S. Democratic senators and security officials have warned Trump against cutting a deal that would do little to curb North Korea's nuclear ambitions.Trump left for Vietnam aboard Air Force One from Joint Base Andrews just outside Washington shortly after 12:30 p.m. EST (1730 GMT) on Monday. He is due to arrive in Hanoi on Tuesday evening, local time.Trump will meet Kim for a brief one-on-one conversation on Wednesday evening, followed by a social dinner, at which they will each be accompanied by two guests and interpreters, White House spokeswoman Sarah Sanders told reporters on Air Force One. She said that would be followed by more meetings between the two leaders on Thursday.She said Trump would be accompanied at the dinner by Secretary of State Mike Pompeo and acting Chief of Staff Mick Mulvaney.Speaking in Washington on Sunday, Trump said he believed he saw eye-to-eye with Kim and that they had developed "a very, very good relationship."Tweeting on Monday, he stressed the benefits to North Korea if it gave up its nuclear weapons. "With complete Denuclearization, North Korea will rapidly become an Economic Powerhouse. Without it, just more of the same. Chairman Kim will make a wise decision!" Trump said.Trump told reporters he and Kim would have "a very tremendous summit."In a speech on Sunday night, Trump, however, appeared to play down any hope of a major breakthrough at the Hanoi summit, saying he would be happy as long as North Korea maintained its pause on weapons testing."I'm not in a rush. I don't want to rush anybody," he said. "I just don't want testing. As long as there's no testing, we're happy."North Korea conducted its last nuclear test in September 2017 and last tested an intercontinental ballistic missile in November 2017.DOMESTIC PRESSURETrump's departure from Washington comes at a time of increased pressure at home.Anticipation has been rising about the impending release of Special Counsel Robert Mueller's report on Russian interference in the 2016 U.S. elections, although a senior U.S. Justice Department official said on Friday it would not come this week.Trump's former lawyer Michael Cohen is due to testify in a public hearing before a U.S. congressional committee on Wednesday, and the panel's chairman said Trump's business practices would be a focus of the testimony.A South Korean presidential spokesman told reporters in Seoul the two sides might be able to agree to a formal end of the Korean War, which ended in an armistice not a peace treaty, a move North Korea has long sought.While a formal peace treaty may be a long way off, the two sides have discussed the possibility of a political declaration stating that the war over."The possibility is there," the spokesman, Kim Eui-kyeom told a briefing in Seoul.Before its testing halt, the North conducted a series of tests that it says has given it the capability of reaching the U.S. mainland with nuclear weapons.The United States has for years demanded North Korea's complete, verifiable and irreversible denuclearization before any concessions will be granted. North Korea denounced that stance as unilateral and "gangster like."In recent days, Trump has signalled a possible softening, saying he would love to be able to remove tough sanctions if there was meaningful progress on denuclearization.Easing of punishing sanctions is a top priority for North Korea. It warned Trump on Sunday not to listen to U.S. critics who it said were disrupting efforts to improve ties. Trump has scoffed at those questioning his handling of North Korea, and added that Chinese President Xi Jinping has been supportive of U.S. efforts.SANCTIONS TO REMAIN IN PLACEIn return for a declaration that the war is over, North Korea could allow international inspectors to observe the dismantlement of its nuclear reactor at Yongbyon, analysts say.The United States could also agree to opening U.S.-North Korea liaison offices and allow some inter-Korean projects, provided the North takes steps toward denuclearization.U.S. Secretary of State Mike Pompeo told CNN on Sunday that core economic sanctions "that prevent countries from conducting trade, creating wealth for North Korea ... are definitely going to remain in place" until complete denuclearization.But he suggested there could be other concessions toward North Korea, such as "exchanges of people, lots of other ways ... if we get a substantial step and move forward."In Geneva, U.N. Secretary-General Antonio Guterres said he hoped the summit would produce "concrete steps for sustainable, peaceful and complete and verifiable denuclearization of the Korean Peninsula."South Korean President Moon Jae-in, who supports opening up North Korea, praised Trump and Kim, saying those opposed to better ties on the peninsula, and between North Korea and the United States, should "discard such biased perspectives".Kim is making his way to Vietnam by train through China and is expected to arrive in Vietnam early on Tuesday.