You might like to think about the way in which Austen uses the motif of acting and drama as a way of satirising the gap between sincerity and insincerity in this excellent novel. We are presented with a world where the rich fluctuate between Bath and London and their country manors. It is therefore very difficult to truly know anybody with conviction. Sincerity is something that therefore becomes very important. It is very hard to distinguish whether somebody is acting or not, as the case with the Crawfords shows. This is particularly relevant when you are trying to chose who you will marry. Austen seems to be satirising a society in which sincerity is something that is so easily feigned and used as a means to deceive others. The importance of acting and the drama in this novel only brings this fact to our awareness more strongly.
In response to this, the character of Fanny Price may be shown to be something of a model for the kind of behaviour that young women should adopt. Her withdrawn and reclusive nature may be an excellent defence against the potential insincerity of male suitors. In a world where there is such a big gap between appearances and reality, perhaps it may be thought safe to withdraw until you have established the veracity or otherwise of the characters around you.