The SK president is very much in favour of reconciliation with the North. I think everyone will come out of it looking good, and will likely be a PR stunt for all involved. SK brokered the deal, their president can spin it as SK being tougher on American influence in the peninsula, Trump will get a concession of some sort, NK will get some sort of sanctions ease, or a reversal of sanctions pending specific conditions projected years in the future (when Trump isn't going to be president), China will take credit for doing background work, and while none of it might mean anything in terms of material changes, it could be a good political move for all involved.
Could even be Trump's Iran moment, only without any binding treaty, or that might be what he's thinking. Judging by the polls, and forecasts for the midterms, he needs something to divert attention from the Russia investigation.