In Dragon Quest IV / Dragon Warrior IV for the NES, at the end of Chapter 4, it says "This is how Mara and Nara, without fulfilling their wish, left their home country." That makes it seem like there's some way for them to actually fulfil their wish (of killing Balzack, presumably). This also seems to be reinforced by the fact that the boat captain doesn't immediately sail the boat, he says "Do you have anything you should take card of before leaving?"
Is it possible for them to fulfil their wish before the end of Chapter 4? If not, why does the boar captain ask that question? Is there something else that can be done before sailing?