"Spare a moment, as you anticipate one of the most unusual summits in modern history, to consider North Korea's leader as he leaves the all-encompassing bubble of his locked-down stronghold of Pyongyang and steps off a jet onto Singapore soil for his planned sit-down with President Donald Trump on Tuesday. There's just no recent precedent for the gamble Kim Jong Un is taking." See: https://www.yahoo.com/news/m/1864f911-cbc9-3ef1-bcd6-f820e65ebe12/ss_isolated-kim-jong-un-takes.html
Although Jong Un went to school in Switzerland, the only other time I can recall him leaving N. Korea was when he visited Beijing earlier this year. For most of us who are not in the spotlight, traveling abroad is awkward at best so for him there has to be a bit of uh, “fear” for lack of better words. No, I haven’t read the link that was provided as of yet but I will definitely do a read later in the day.
Plus, he probably has to worry about what is going on back in North Korea while he is gone. That's the real concern, I think. He hasn't exactly ruled through benevolence.