The film depends on a reliable fictional element, the redeeming power of the love of a good woman. Dexter is a superficial fool who descends through ever-lowering levels of humiliation on TV, cable and the Internet, until he has been reduced to a punchline. Emma stays her course. Her persistence and success are like a rebuke to Dexter. But it is important for us, and Emma, to realize that he is fundamentally a good person at heart — potentially.