What are the chances that North Korea actually gives up its nuclear weapons?
No one really knows because we know little about the way that the North Korean regime thinks. This is even more true since the death of Kim Jong-Il. We do not know what Kim Jong-un thinks and we don't know how firm his hold on power is.
My own feeling is that there is very little chance that the North will give up its weapons. They seem to be the only thing that it has that it can use to ensure that other countries will pay attention to it and that they will give it aid if needed. For this reason, it seems very unlikely that they would disarm.
I think the chances of that happening in reality are very low. The North Koreans have consistently used their nuclear weapons as a bargaining chip to gain more assistance from other countries and have also relied heavily on them to maintain their security. They are unlikely to give up on them since doing so would only increase their vulnerability, especially vis-a-vis the Americans. Such an outcome would be unacceptable to them.