Have you noticed that this is a two way street and we are seeing some of the closest things to conventional diplomacy for both administrations?
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Kim no longer calls POTUS "A mentally deranged US dotard" or refer to Americans as "ugly gnomes" and Trump no longer refers to Kim as "Little Rocket Man" or "[That] maniac sitting there."  POTUS even refers to Kim as a great guy who loves his people; an incomplete thought that should have been "loves his people TO DEATH."  
http://www.nytimes.com/2018/03/09/world/asia/trump-kim-jong-un.html
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Trump has backed off on several things, as well, such as cutting back on joint military drills with South Korea, etc.. Did Kim's threats of nuclear annihilation bring Trump to his knees? Or was is the "dotard" comment?  
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I am looking forward to further diplomatic discussions and occasional unilateral or bilateral concessions from both sides. (Food aid? Reduced sanctions? The allowance of UN or other international inspection of NK nuclear facilities? Who knows?)  One major problem is that both heads of state are egomaniacs who can derail progress for personal, petty reasons. I hope that their professional staff will keep things on track.
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The bigger problem I see is in the future: As NK and SK approach informal or even formal unification and SK begins to fund economic development of the North, it will be another challenge to the US economically. Post-WWII, a number of US industries were hurt by rebounding Western European growth (but helped by regrowth of Euro markets). The Italian shoe industry pretty much ended US shoe manufacturing. Japan's post-WWII recovery affected US cars and electronics. After the Korean War Armistice, SK took off and SK steel, cars, electronics have challenged US dominance. Nixon opened up China; both economies have grown enormously, but not without harm to US manufacturing and intellectual property. When Communist Vietnam realized that they were being left behind, they became capitalists and have grown tremendously in some sectors. When SK-NK join economic forces, it will open new markets in the north that will probably go to mostly to China, SK, Taiwan and Japan. SK will probably build new factories to exploit the new, cheap labor force and grow to dominate some other sector (cheap industrial robots that will eliminate more US jobs?).