Here's what we know - and don't know.
January 1, 2017: Kim Jong Un says in a New Year's address that preparations for launching an intercontinental ballistic missile have "reached the final stage". Tillerson said the decision to agree to the meeting was "a decision the president took himself". "It's possible the summit will be in the Panmunjom DMZ border complex".
He warned a meeting between the two leaders poses real security risks.
Trump took office vowing to stop North Korea from attaining a nuclear-tipped missile that could reach the USA mainland, a goal that Pyongyang is on the cusp of reaching.
Jim Hoare, former Foreign Office diplomat who helped set up the British embassy in Pyongyang from 2001 to 2002, spoke to The Sun Online about China's deteriorating relationship with North Korea.
Determined not to be left behind, a Chinese state-run paper ran an editorial this week declaring that the Korean issue can not be solved without the participation of China (in addition to Russian Federation and the UN Security Council).
The best outcome would be that Trump uses his purported deal-making skills to agree to a peace treaty with North Korea, a deal that denuclearises the Korean Peninsula, scales back the USA military presence there and institutes normal diplomatic relations with Pyongyang. North Korea has long protested the military manoeuvrs south of the divided Korean Peninsula as a rehearsal for invading the North.
On Twitter Thursday, Trump claimed he had already succeeded in helping to earn concessions from North Korea.
But it will take time and work before the U.S. and North Korea can get to the point of negotiating, analysts and officials say.
"He will make demands that he knows we will never agree to, like the USA abandoning South Korea", said Rubio. If Trump had declined, it would have created "serious friction" with Moon and his pursuit of peace on the Korean peninsula, Mount said.
"I think pressure has certainly brought us to this point".
"Pyongyang can say they tried and resume nuclear and missile testing", he said. Those stocks are often compared to bonds and they tend to fall when yields move higher, as higher yields make them less appealing to investors seeking income.
What does the United States want?Just last August he threatened to "unleash fire and fury" on North Korea if provoked.
Kim's sudden change of heart didn't come out of nowhere-Beijing has been turning the screws on Pyongyang lately by actually enforcing worldwide sanctions against the Kim regime, another positive sign that talks may prove fruitful this go-round. US policy has long resisted offering any validation to the rogue regime - validation it could then leverage geopolitically.
It's not clear. It could be that years of sanctions designed force it to talk are working.
What do the South Koreans think?
After Pyongyang sent a delegation to the 2018 Winter Olympics in and the two Koreas fielded a joint team, it was announced by negotiators from Seoul that the North Koreans were willing to open a dialogue with the US.
Kim "expressed his eagerness to meet President Trump as soon as possible", Chung told reporters. And now that China is gunning to take the global leadership mantle from the United States, that reputation is more important to Beijing than ever.
"(It could mean) a withdrawal of U.S. troops from South Korea and withdrawing the USA nuclear umbrella over South Korea and Japan", Kim said.
So far Mr. Trump is insisting his "maximum pressure" campaign of sanctioning and isolating North Korea will continue, and there is no indication of what, if anything, he might be prepared to give North Korea if it limits the nuclear program in a verifiable way.
Until this week, Rodman was believed to be the only person who had met both Trump and Kim. Under the terms of that agreement, North Korea agreed to freeze and ultimately dismantle its nuclear programme in exchange for "the full normalisation of political and economic relations with the US".
Lawmaker wants to question businessman in Mueller probe: In other Mueller news, the top Democrat on the House intelligence committee - Rep. Adam Schiff of California - said on Thursday that he wants to question George Nader, a Lebanese-American businessman who is cooperating with special counsel Mueller.
Experts have low expectations for the outcome of the meeting, if indeed it goes ahead.
"We've seen this movie so many times before", said Duyeon Kim. Is it North Korea or is it China that is putting denuclearization on the table?
"I explained to President Trump that his leadership and his maximum pressure policy, together with worldwide solidarity, brought us to this juncture". "He didn't, and he got a USA state visit".
Trump and Kim are completely different, but at the same time paradoxically resemble.