They have a past history of playing games with South Korea, making nice than pulling the chain again. So anything they say has to be down and in writing, plus verify, verify and verify.
Via Daily Caller:
President Donald Trump released a letter he received from Kim Jong Un Thursday expressing hope for the future of relations between North Korea and the United States.
The letter from Kim Jong Un is dated July 6, which predates the recent visit of U.S. Secretary of State Mike Pompeo to Pyongyang.
The letter expresses optimism for the next meeting between the two leaders but does not make any mention or commitment to denuclearization. Instead, the letter is peppered with flowery language such as the “start of a meaningful journey” and “improvement of relations.”