Kim Jung Un is a clown in the global carnival, and just like a clown he does not run the show.
North Korea does over 75%-90% of their trade with China (depending on source)
Without the massive amounts of food and fuel that some in from China, North Korea would starve and not function.
Every time a new president is elected and talks about fixing trade imbalances with China-North Korea starts acting up and testing missiles, China offers to help they back down; we don't bring up trade afterwards-China looks good.
In a linked transcript of a call with Trump and Duterte of the Philippines both expressed the sentiments that China ultimately held influence over North Korea.
North Korea is China's nasty junkyard dog on a string. If someone is coming towards you with a nasty dog on a string...do you talk to the dog and try to reason with it or do you talk to the one holding the string?
Check out my video on solution to the North Korean Crisis explained in 4 mins