TOKYO — North Korea’s Kim Jong Un was all broad smiles and hearty handshakes during an unprecedented meeting with South Korean envoys this week, one in which he agreed to talk to his archenemy in Washington and stop missile and nuclear tests while dialogue continues.

Were they the smiles of an authoritarian leader under pressure, a man desperately trying to smooth talk his way out of sanctions that threaten the stability of his regime? A man increasingly alarmed that the unpredictable U.S. president might be serious about military strikes?

Or were they the smiles of an authoritarian leader who feels supremely confident in his position? A man who declared at the end of last year that he’d “completed” his missile program and is now ready to deal with the United States — on an equal footing?

As with many things about the world’s most impenetrable country, there is plenty of speculation but little in the way of fact.

“What is Kim Jong Un trying to get out of this?” asked Gordon Flake, a longtime Korea expert in Washington who is now at the University of Western Australia’s Perth USAsia Center. “I don’t know and I don’t think he knows.”

In the six years that he has been in power, Kim has defied all expectations. Despite taking over the family business at age 27 and having no military or political experience, he has secured control of a regime founded by his grandfather when Harry S. Truman was president of the United States.

Last year, he oversaw a series of missile launches that disproved skepticism that North Korea would ever be able to build an intercontinental ballistic missile capable of reaching all of the United States. And his nuclear scientists detonated a hydrogen bomb for the first time.

But the international sanctions imposed by the United Nations as punishments for those developments — sanctions that targeted core parts of the economy, including coal, seafood and garment exports — are now thought to be affecting the North Korean regime.

As the United States leads a “maximum pressure” campaign, China, North Korea’s biggest trading partner, appears to be joining in, perhaps convinced that the alternative is war.

“Now China faces three bad options, not two,” said Andrei Lankov, a professor at Kookmin University in Seoul who studied at Kim Il Sung University in Pyongyang. “The bad option is a stable nuclear North Korea. The worse option is North Korea in a state of political crisis. And the worst option is war.”

Concerned that President Trump is serious in threatening to “totally destroy” North Korea, the government in Beijing seems to have updated its previously halfhearted approach to sanctions to something more serious — even if this risks destabilizing the regime in Pyongyang and sending floods of refugees into China.

“A war is worse than instability,” Lankov said. “So for the time being, China is on board.” 

Is this what caused Kim’s sudden interest in rapprochement with South Korea and, potentially, the United States? Kim is scheduled to meet the South’s president, Moon Jae-in, next month at a summit just over the southern side of the line that divides the Koreas.

Nam Sung-wook, a professor of North Korean studies at Korea University in Seoul, thinks so.

“The primary motive behind Kim Jong Un’s recent moves is to surmount the difficulties from their growing isolation,” he said. 

“The sanctions are starting to take a toll on North Korea as support from China and Russia is waning,” Nam said. “This is bringing North Korea out and leading it to open up to South Korea.”  

In addition to the international sanctions, the United States has begun a crackdown on North Korean shipping activities, and its ally, Japan, has caught several illegal transfers at sea. This is further crimping North Korea’s ability to evade sanctions.

But, less palatably for the outside world, there is evidence to suggest that Kim’s receptiveness to talks is because he’s feeling strong.

“The recent opening up could be a strategic move to gain recognition as a legitimate nuclear state in the eyes of the outside world,” said Koo Hae-woo, a former deputy head of South Korea’s intelligence service. “Kim Jong Un wants to talk with the U.S. on a level playing field and to talk about mutual arms reduction with [the] U.S., rather than the unilateral denuclearization of North Korea.”

Indeed, the Rodong Sinmun, North Korea’s main newspaper, issued another tirade against the United States’ nuclear weapons this week.

“Not content with becoming first in imposing the nuclear holocaust on humankind, the U.S. is getting keen on nuclear weapons modernization in order to hold an absolute nuclear edge in the world,” the paper said, adding that this proved why North Korea needed a nuclear deterrent.

More evidence of confidence — or of desperation, depending on perspective — comes in Kim’s apparent willingness to travel to the demilitarized zone (DMZ) that separates the Koreas for the summit with Moon.

The two previous summits, between Moon’s progressive predecessors and Kim’s father, took place in Pyongyang.

But Kim and Moon are set to meet at Peace House, just over the southern side of the border line that runs through the Panmunjom truce village in the DMZ.

“Compared to the past two inter-Korean summits, which were more about displaying amity, the fact that the upcoming summit is at Panmunjom, not in Pyongyang, shows that Kim is actually interested in having a hands-on discussion with the South,” said Cheong Seong-chang, a North Korean leadership expert at the Sejong Institute near Seoul. 

Their plan to open a leader-to-leader hotline also shows Kim’s intention to make sure this is not a one-time conversation but a continuing one, Cheong said.

Experts were also startled that Kim invited the South Korean envoys into the headquarters of the ruling Workers’ Party headquarters for a cordial dinner with him and his wife, Ri Sol Ju.

“Compared to the reclusive leadership of his father and grandfather, Kim Jong Un has been displaying a bolder and more proactive style of leadership. They used to wait until the final moment to meet envoys, and never brought their wives to such meetings,” said Nam of Korea University.

 “But Kim Jong Un did. He’s trying present North Korea as a ‘normal’ state, rather than an uncivilized, barbarous state that the world thinks it is,” he said.

Min Joo Kim in Seoul contributed to this report.