This is a significant development for the simple reason that Kim needs to continue to build popular support for his cause if he hopes to prevail in the long-term. In that regard, the lifting of sanctions is not nearly as important as Kim's broader goal of ending Washington's military occupation of the Korean peninsula and reunifying the country. In order to achieve those objectives, Kim will need the support of his allies in Moscow and Beijing as well as that of the Korean people. His disciplined performance in Hanoi suggests that he is entirely deserving of that support.

There's no way to know whether Kim expected President Trump to put the kibosh on the deal or not. But with uber-hawks like Mike Pompeo and John Bolton at the bargaining table, he must have figured that there was a high probability of failure. Was that why Kim made such a generous offer during the negotiations? Was it part of a plan to make him look good because he knew Trump would throw a wrench in the works?