This is my take on the matter:
There are reasons to be a bit skeptical. As pointed out by many, it is probably against the present interests of DPRK’s regime to abandon its nuclear arms. By the end of the day, this is probably seen as the only guaranty against foreign intervention. The history of Libya may be seen as a warning.
On the other hand, the recent overture to the Olympic games raises questions about what DPRK really wants. Sweet words of reunification have been uttered and a dialogue with South Korea has been established. While it may sound to good to be true, there is only one way to find out.
What about Kim Jong Un’s trustworthiness? We need to keep in mind that since he came to power in 2011, he himself has been never involved in negotiations with the US. What ever happened in the past, it would be unwise to reject his offer based on the record of previous DPRK leaders.
But even if one does not trust him, what is there to lose? Jong-un has not stated that sanctions have to be lifted before a dialogue can take place. So, the dialogue may begin, without the US having to give any prior concessions. What possible agreement the parties can reach is another question.
Trump's early tweet on the matter reads;
Possible progress being made in talks with North Korea. For the first time in many years, a serious effort is being made by all parties concerned. The World is watching and waiting! May be false hope, but the U.S. is ready to go hard in either direction!
So, Trump is waving a carrot and a stick. I suggest it is time to put the stick aside for a while and grab the opportunity. This may be the best chance the US ever gets.