"Well, Kim Jong-un got back on his hands and knees and begged for it, which is exactly the position you want to put him in".
Giuliani, the former mayor of NY, made the comments at a conference in Israel.
"If China does provide the escort, it may be a message directed at the US-ROK alliance that China is strongly backing up the Kim regime", the source said, referring to South Korea's official name, the Republic of Korea.
Expectations run high that the two leaders will emerge from the summit with an agreement to formally end the Korean War after a 60-year standoff and a commitment to dismantling the North's nuclear arsenal and long-range missiles.
Trump announced the historic summit was back on track last Friday after an hour-long meeting with the top North Korean official.
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Before threatening to walk away from talks the first time, North Korea had bemoaned American attempts to "drive us into a corner" and force disarmament.
Bolton has not commented publicly since the president distanced himself from the Libya comparison and the White House insisted he would follow the "Trump model".
But only 20% of Americans say they think North Korea will ever give up its nuclear weapons - the express goal of any negotiations.
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The pair will attend the official opening of the Storehouse Theatre, a lunch at Chester Town Hall and also open a new bridge. While this might seem standard practice for royal engagements with the Queen, this is actually quite a first.
The White House has kept the focus on the Singapore meeting, viewing it as the crucial first step toward resolving the North Korea threat.
Bill Clinton nearly met with then-leader Kim Jong Il in 2000, but in the end sent Secretary of State Madeleine Albright instead.
Talks will begin at Capella Hotel on Singapore's Sentosa Island at 9 am on 12 June.
A farcical note will be added by the eccentric former National Basketball Association star Dennis Rodman, who is considering traveling to Singapore a day before the U.S.
But North Korea responded harshly.
Preparations are continuing for the summit, with Singapore's Foreign Minister Vivian Balakrishnan travelling to Pyongyang on Thursday for a two-day visit as part of the diplomatic flurry.
According to Bloomberg, Trump is toying with the idea of inviting Kim to his Mar-a-Lago resort in Florida for a second meeting, depending on the results of the June 12 summit.
Facilities include a sunny portico and the circular Grand Ballroom with a glass-domed skylight and room for 400 guests, popular for wedding receptions that can cost up to $1,800 a table.