But North Korea is at a sensitive stage of negotiations to end its nuclear programme in exchange for security guarantees and aid, leading some diplomats to cast doubt on the likelihood that Kim would cross Americas red line forbidding the proliferation of nuclear materials.
Diplomats, by their very nature tend to believe in the good in people. The must believe that all leaders are basically honest and their word can be trusted. Without that belief there would be no such thing as diplomacy.
In my undiplomatic opinion, Kim is once again using his nuclear weapons program to extort money from the US. If he can make money by selling nuclear materials to other countries he will continue to do so. If he can hide material and equipment in another country he will do so. When he has extorted as much as he can it will be retrieved and if caught hell apologize and start the whole extortion thing again.
They are skilled at wordsmithing for days on end in barricaded rooms, all the while totally detached from both the larger reality of things outside those rooms, and the patent dishonesty of patently dishonest people whom they project their naive, Judeo-Christian, Western (and often elitist Ivy League) faith upon.