Depiction of working-class life in The Princess Casamassima: realism? sentimentality? or cynicism?

So Paul Muniment, the working-class radical who has befriended "our hero," Hyacinth, wanrs him that the eponymous Princess Casamassima is a "monster." What can that mean? Somehow he sense what Hyacinth feared initially: that the P.C. thinks she's on the side of the working class, that she thinks she wants to dedicate her life to social justice and equality, but that in fact she is using others and likely to destroy the lives of others in the process. We'll see how this plays out - but it's clear that Hyacinth is setting himself up as a victim, totally smitten of the beauty of the P.C., and likely to do anything for her - which will inevitably lead to tragedy and destruction. Meanwhile, Paul is smitten with another aristocratic lady, Lady Aurora, who has devoted herself to helping Paul's invalid sister, Rosy. I suspect that she will continue to be a very good-hearted and thoughtful person - a contrast to the Princess. It's striking how this second part of the P.C. gradually drifts toward the milieu of the aristocracy: drawing rooms, townhouses, etc. - this is a world in which Henry James felt more at ease, obviously, but we have to give him credit for, at least in the first part of the P.C., some very moving and evocative descriptions of the misery of working-class lives in late 19th-century England, and I hope he maintains that sensibility throughout the novel and doesn't succumb to Dickensian sentimentality or Conradian cynicism.