Ganya

The final chapters of Part 3 reveals Aglaia's desire to marry Myshkin and the latter's willingness to consent.  At the beginning of Part 4, Ganya is informed by his sister Adelaida of the engagement, and, surprisingly, does not appear to be perturbed by the revelation.  Though in love with Aglaia himself, Ganya resignedly accepts the ensuing marriage as a done deal.   Instead, he is more worried about his father being found out a thief. 

Ganya is a man of "violent and envious cravings," desperately desiring "to prove to himself that he [is] a man of great independence."  He has given up his job as secretary to General Epanchin and has no idea what to do now, though he feels he will have success of some significance.  Myshkin identified him in Part 1 as one who strongly desires to be original.  Marrying Natasya  was one attempt at originality, having no love for her and only desiring the monetary gains to be enjoyed by the match.  The lack of originality causes 'the continual mortification of his vanity" to be even  greater.

Why is Aglaia not interested in Ganya?  One only need to remember her recitation of "The Poor Knight" to know what attracts her to Myshkin.  Myshkin grasped an ideal and believed in it, despite what others said.  There is no ideal in mind for Ganya.  As a matter of fact, one is not sure what he really stands for.  The arranged marriage with Natasya shows he is corruptible.  There is no innocent quality about him like there is about Myshkin.