"I had not thought Mr. Darcy so bad as this -- though I have never liked him, I had not thought so very ill of him. -- I had supposed him to be despising his fellow-creatures in general, but did not suspect him of descending to such malicious revenge, such injustice, such inhumanity as this!" After a few minutes reflection, however, she continued -- "I do remember his boasting one day, at Netherfield, of the implacability of his resentments, of his having an unforgiving temper. His disposition must be dreadful." (Chapter 16)

When Wickham told his story to Lizzy in Chapter 16 she also listened to him and then looked back on her interactions with Darcy to verify Wickham’s story. At the Netherfield ball Mr. Denny claimed Wickham avoided the ball to avoid Darcy and he confirms it himself in Chapter 21 to Lizzy. Each time Wickham tells his story there is someone to confirm it. Both Lizzy and Aunt Gardiner believe him and then look back on their memory to confirm his story, neither look to disprove his story. I think it attests to the power of Wickham’s charming manners and his believability. Lizzy is not the only person who sees truth in his looks.

Wickham's society was of material service in dispelling the gloom which the late perverse occurrences had thrown on many of the Longbourn family. They saw him often, and to his other recommendations was now added that of general unreserve. The whole of what Elizabeth had already heard, his claims on Mr. Darcy, and all that he had suffered from him, was now openly acknowledged and publicly canvassed; and everybody was pleased to think how much they had always disliked Mr. Darcy before they had known anything of the matter. (Chapter 24)

After Miss Bingley’s letter arrived informing Jane their party was settled in London for the winter; Mrs. Bennet loudly and constantly laments Bingley’s absence to the distress of Jane. Wickham then divulges his story of mistreatment at the hands of Darcy to everyone who believes him in part because it confirms their dislike of Darcy since the Meryton assembly ball—just in case anyone was ready to forgive him his ill-mannered ways this new information prevents it. (;D) Wickham is now the darling of Meryton and Longbourn house with even some claim on the capricious Mr. Bennet. In Chapter 24 Mr. Bennet jokes to Lizzy about Wickham, “He is a pleasant fellow, and would jilt you creditably” and in Lizzy tells Aunt Gardiner her father is partial to Wickham in Chapter 26.

Miss Bennet was the only creature who could suppose there might be any extenuating circumstances in the case, unknown to the society of Hertfordshire; her mild and steady candour always pleaded for allowances, and urged the possibility of mistakes -- but by everybody else Mr. Darcy was condemned as the worst of men. (Chapter 24)

Wickham has made a good impression on everyone and his story is accepted by all but Jane who is the only person who does not believe Darcy is the worst of men. The only people who ever questioned Wickham's story of woe were those of the party at Netherfield and now they are too far away to be aware their friend is in need of their defense again. Miss Bingley would surely rally to the challenge. (;D) There will be no repeat of the conflicting reports of Darcy Lizzy received at the Netherfield ball; Wickham has the stage all to himself. ;D