This is not clear from the first watching of the film, but if you watch it the second time from the specific angle of Marquise de Merteuil behaviour as a sociopath, you can probably learn a few things about this condition.Similarly in Fatal Attraction you see how relentless they can stack the victim, using everything to keep the person on a short leash.A lot of tragedies could be avoided, if people who are facing something strange or inconsistent in behaviour simply take the time to ask, "What else could this mean?"Can it be explained as an attempt of manipulation, or bold faced lie?" Paradoxically, most of the victims of female sociopaths are woman.
They have no boundaries and are ready to go to the bitter end to achieve their goal. They typically have high IQ which makes them even more dangerous if they are a member of your family or girlfriend. Demanding, ruthless, two-faced, manipulative, relentless and very methodical bullies.
"Her regular tantrums involve swearing, shouting, intimidation and threatens.
She will wear people down until, for a quieter life, they agree with her.
We will distinguish the term "sociopath" and "psychopath" based on physical violence: psychopath is sociopath who routinely or even predominantly uses physical violence. Female sociopaths rarely use physical violence and can much better mask their real intentions then make psychopaths.
They are more patient (although the term patience and sociopath are mutually contradictive -- they are after instant gratification) and can hunt for a pray somewhat longer. And probably are more dangerous when you have them close by.
Despite inability to feels love, they can imitate it and they are often seductive.