The next day, Elizabeth meets Mr. Darcy out on her walk. He has been looking for her and he hands her a letter that he has written.
In the letter, he addresses first the charge that he considers least serious, that of his willful and deliberate acts to prevent Jane and Mr. Bingley's engagement. He had not felt that Jane really loved Mr. Bingley, though he now realizes he was mistaken. He was concerned by the behavior of all members of the Bennet family, with the exception of Jane and Elizabeth herself.
He has no shame for playing a part in all this, but he feels that it was beneath him to have prevented Mr. Bingley from knowing that Jane was in London. He does regret that.
As for Wickham, Darcy writes that he had indeed carried out his father's wishes and given Wickham an inheritance, but Wickham squandered the money and then asked for more. When Darcy refused, Wickham managed to worm his way into Darcy's little sister Georgiana's heart and tried to elope with her. She was only fifteen.