The problem with personality disorders such as Narcissism and Borderline is the lack of insight that is needed for change and growth. This means there is a certain lack of self reflection that is a precursor to peace of mind. We need to have insight into the way the mind operates to be able to change its course. Narcissists do not delve deeply beneath the surface in this way. They are more interested in immediate gratification of their primary desires for praise and adulation. They also shift the blame onto others and nothing is ever their fault.
Impressing strangers is more important to Narcissists than being good to those who are near and dear. They restlessly seek praise from random people they just met, while simultaneously treating the ones who actually care about them like trash (except when they need them for something). So peace can never be found. Strangers can give you praise. But they are strangers after all and go home after the performance is over. Meanwhile, Narcissists have burned their bridges with the ones that stood by and loved them.
Finally, Narcissists feel a void inside that must be filled with illusions they create. Instead of seeking the fountain of tranquility within, they look outside for the next feeding. They try to build a facade that will be lovable but they know it is fake and therefore can never feel truly secure or at peace. So, like the rest of us, if we are constantly driven by the frightened, greedy little mind, Narcissists will never find peace.