That Syria thread is in danger of going off topic. So let's revive this one.
Seems to me The Donald is likely to cut a deal with the PRC. But first he has to show how tough he is. And South Korea of course has a stake.
What I see happening: something unacceptably awful happens in North Korea. South Korea invades with US support. China counter-invades. They meet at some point... and then the diplomats divvy the territory up right where the armies meet up.
There's historical precedent for this. I figure both sides want a short, limited war followed by a more-or-less sustainable peace. The current cease fire lasted decades. Why shouldn't this arrangement do as well?
China officially gains territory and shows its toughness, thus saving face. South Korea gains territory both officially and in reality. North Korea is finished and no one will miss it.
Of course it won't last forever. Nothing does. This avoids a much larger war, or at the very least kicks the can way down the road. Good enough.
`Nuther scenario: US and South Korea destroy all the Nork nuke and missile sites, prepare to invade. Beijing makes a big stink. The Donald offers this deal: North Korea is banned from having any military forces and becomes a protectorate of China, but US and SK have the right to frequent inspections.
The Kim dynasty would have a hard time surviving such a loss of face. China would enforce a Communist regime, but the locals would keep giving them grief. Eventually they'd get tired of dealing with all the unrest, and be ready to make more concessions.