You don’t get a deal done with North Korea by just targeting North Korea with sanctions, China and Russia have North Koreas back.
You need to create leverage both economically and militarily against China and Russia (which has happened, and is happening) then China and Russia want to reopen 6 party talks (under discussion and will happen soon).
Then everybody needs to look like a winner in front of their people. I suggest reading the article I just posted in my previous post. The same source I just posted, posted this a month or so ago.
The six party talks will be essentially a Marshal Plan of sorts for North Korea. Japan, South Korea, The United States, China, Russia and North Korea will enter into a set of negotiations publicly sold as engaging in diplomacy and reducing tension.
Strategy - Will President Trump Break Norms and Arrange Meeting With Kim Jong-un? Indications Point Toward Yes... - The Last Refuge
Note Trumps reference to the Marshal Plan in yesterdays UN speech. I suspect that will come up later with regards 6 party talks.
It was in the same period exactly 70 years ago that the United States developed the Marshall Plan to help restore Europe. Those these beautiful pillars, they are pillars of peace, sovereignty, security, and prosperity. The Marshall Plan was built on the noble idea that the whole world is safer when nations are strong, independent, and free.