No, I have made no such pretension. I have faults enough, but they are not, I hope, of understanding. My temper I dare not vouch for. It is, I believe, too little yielding – certainly too little for the convenience of the world. I cannot forget the follies and vices of others so soon as I ought, nor their offences against myself. My feelings are not puffed about with every attempt to move them. My temper would perhaps be called resentful. My good opinion once lost, is lost forever.

– Jane Austen

Pride and Prejudice, Chapter 11. This is Darcy’s response to Elizabeth telling him that he has no defect and "owns it himself without disguise." Here he acknowledges his central flaw, having a resentful character and unforgiving temper towards the vices and offenses of others. He is being honest and displaying integrity here in placing a high value on "good opinion" and reputation. That shows a certain self-awareness about his flaws. But also there is an irony here, as he is not aware of how proud he sounds, as he proudly boasts about his resentful nature.