You only need to look at previous attempts by the international community (and the US in particular) to even bring North Korea to the negotiating table, let alone to openly discuss the prospect of dropping their nuclear ambitions and/or ending hostilities between DPRK and the South. Trump decided to throw away the official 'How to deal with North Korea' playbook (you know, since it has worked so well thus far) and basically stop pussyfooting around.
I reckon Trump deserves a great deal of credit - yet he could still find it all slip away if it turns out that this is all yet another ploy by the Kim regime to buy time, score political points and to get one over on the US - we had all better hope that this is not the case.