Pride can be both a fault and an asset. Consider how Mr. Darcy's pride, at first, renders him rude and disagreeable, turning against him the woman he grows to love. However, when Elizabeth wounds him with her rejection of his proposal, saying that he didn't behave in a very gentlemanlike manner, it is pride that compels Darcy to reevaluate his behavior and change for the better. We might also consider how Elizabeth's pride in her own discernment -- a pride that eventually reveals itself as misplaced -- blinds her to the deceitfulness of Mr. Wickham and the good qualities of Mr. Darcy (at least, initially). However, it is also Elizabeth's pride, in part, that will not permit her to accept the ridiculous proposal of her cousin, Mr. Collins, and this saves her from a lifetime of disappointment and humiliation (and the kind of marriage that her mother and father have).
Society often presents upper-class women with an untenable choice: become a spinster or marry a fool. Consider Charlotte Collins nee Lucas. As a twenty-seven-year-old woman of little beauty and no fortune, she cannot afford to be romantic, even if she wanted to be. She desires to be established, to have her own "situation," at best, because she so longs not to become a burden on her family. Faced with spinsterhood, Charlotte jumps at the opportunity to marry, even someone as absolutely ridiculous as Mr. Collins. This is precisely the scenario that faces the Bennet girls (and why Mrs. Bennet is so angry when Elizabeth turns down Collins, the man set to inherit Longbourn when Mr. Bennet dies).