If I endeavor to undeceive people as to the rest of his conduct, who will believe me? The general prejudice against Mr. Darcy is so violent that it would be the death of half the good people in Meryton, to attempt to place him in an amiable light.
– Jane Austen
Pride and Prejudice, Chapter 40. Elizabeth decides that it is better not to reveal the true noble nature of Mr. Darcy’s dealings with Wickham. She accepts that she has done an injustice to Darcy with her misjudgment of him. But she does nothing to correct the false perception of him since the prejudice against him is so strong she believes that she cannot overcome it. So people will continue to deceive themselves about Darcy until they find out for themselves.