Meh, there's hunger in North Korea just like there's hunger in the US and other countries. The thing is that America is pretty much enforcing that hunger, so it's kind of like blaming North Korea for feeling the results of something caused by American Imperialism.
But even if he did change his mind because of his country's alleged famine, that's good enough, no?
But in reality it's more likely the case that now that he has nukes, he can finally get proper negotiations going with the South and the US. Leverage is everything.
I don't know why you are taking a dismissive stance towards the hunger issue in N Korea or even comparing it to other countries (particularly the US) when it is very real (and has been for a long time) and not at all comparable to the US in particular.
As much as I don't care for American influence in the region, squarely placing all the blame at their feet is misleading at best and definitely a misrepresentation of events there.