Forecasts suggest that the talks will be protracted with NK seeking the complete removal of all sanctions probably plus, a finacial aid package.
Analysis I've seen suggests that talks may continue well beyond the Trump administration.
The bottom line I think, is that NK is literally on it's uppers and simply cannot continue with sanctions in place, NK is in talks because it HAS to, not because of Trump IMHO, he just happens to be in place at the right time.
KIJ, played a blinder, accelerating his rocket tests to raise the apparent urgency in the region just when he needed to.