Given a few people have commented on this, I'll chime in. I don't believe that the North Korean promise to halt weapons testing is genuine, nor do I believe they have any interest at all in "de-nuclearising" the Korean peninsula. The entire purpose of Kim Jong Un's pursuit of nuclear weapons was based in the long-standing narrative that North Korea faces an existential threat in the face of American military power, and the only way for them to effectively counter that is to acquire nuclear weapons to act as a deterrent. What's changed?
For the record, no the rapprochement over the Winter Olympics doesn't constitute change. At least, not sufficiently to make NK come to the table accepting the US/SK military exercises, promising unilaterally not to test any more missiles, and claiming to want to trade away their very newly acquired nukes for unspecified diplomatic benefits. I don't think even the Chinese restrictions would be enough to make them give up their nukes now that they have them, and I'm inherently suspicious of any statement from NK that implies or states that they are.
So why now? It seems like, following the more or less successful tests they've undertaken with no regard for anyone, they're satisfied with their capability and can now start exploiting it for political gain. I'd say that they're hoping to get the lifting of some sanctions, probably especially from sympathetic China, for the promise of disarming. But they won't actually allow anyone independent in to verify this. That has precedent in the past, and would make sense for what they're probably looking to achieve with this. The government in South Korea has enabled this by being willing to enter into dialogue with NK and only too happy to go along with the fantasy of a united Korea with a Kim in power in the North by fielding a united hockey team and accepting their dignitaries to sit in the same box as other world leaders despite being complicit in industrial scale human rights abuses and the effective imprisonment of an entire population.
Why Trump though? I can only assume they believe that he is actually an old fool, because most people in the rest of the world think that. Of course the office of the President should be respected, and it does carry power in it, but the person currently occupying it really shouldn't be there in terms of competence or skill in politics or diplomacy (at least when it comes to interpersonal skills). So what possibility would a face-to-face meeting between Kim Jong Un and Donald Trump have to backfire? Infinite. What possibility would it have of actually leading to a denuclearised NK? Miniscule. Is it worth taking that risk? In the absence of any better option, taking the chance that it could work is better than resigning ourselves to a hostile pariah state in Korea, but I'm not holding my breath.
Of course, if it does work out and Trump ends up with a fucking Nobel Peace Prize it'll vindicate my theory that Obama and Trump are like polar opposites: Obama started as a politician and President who got a Nobel Peace Prize before he really did anything and
turned into a reality TV star. Trump started as a reality TV star who then became President and won a Nobel Peace Prize. But then my world will collapse and the fabric of the universe will tear and then who will save us?