Pride and self-deception
Both Elizabeth and Darcy are intelligent people who are wrong about important things because their pride gets in the way. Darcy's pride makes him act superior. Elizabeth's pride makes her cling to her first judgment of him. The novel tracks how both characters force themselves to see clearly.
Marriage as economic necessity
For women in Regency England, marriage was not just romantic, it was financial. The Bennet sisters need to marry or face poverty. Austen shows this pressure without sentimentalizing it. Charlotte's practical marriage to Collins makes the stakes concrete.
Class and social mobility
Darcy's world is obsessed with rank. His aunt Lady Catherine treats social hierarchy as a moral order. The novel pushes back by showing that good character does not follow class lines. The Gardiners, who are in trade, behave better than most of the aristocrats.
Appearance versus reality
Wickham looks trustworthy and is not. Darcy looks arrogant and is more decent than he appears. Bingley's sisters look friendly and are calculating. The novel repeatedly shows that surfaces mislead, and that figuring out who someone actually is takes time and honesty.
Women's limited agency
Women in this novel cannot inherit property, cannot easily refuse marriage without consequences, and depend on men to act on their behalf. Austen shows this clearly without turning it into a lecture. Elizabeth's refusals of Collins and Darcy's first proposal are acts of real courage given what she stands to lose.