They are young in the ways of the world, and not yet open to the mortifying conviction that handsome young men must have something to live on as well as the plain” – P&P
Elizabeth Bennet doesn’t begrudge Mr Wickham his attempts to marry Mary King for her dowry (at the time). Austen’s refers to her being “less clear-sighted perhaps in this case than in Charlotte’s,” indicating that his flattery of her and her belief that “she would have been his only choice, had fortune permitted it” has clouded her judgement.
Lizzy “did not quarrel with [Wickham] for his wish of independence” but thinks Charlotte has “sacrificed every better feeling to worldly advantage.” Perhaps because she sees “Charlotte, the wife of Mr. Collins, [as] a most humiliating picture.” There is no comfort or consolation like there is with Wickham’s choice.
Wickham is described as handsome, but twice Mrs Bennet calls Charlotte “very plain.” Perhaps Austen is subtly providing another comparison of the situations: Charlotte is the plain young (wo)man who “must have something to live on.”