Indeed, if Darcy had tried to give Lizzy a verbal account of Wickham's misdeeds, it would not stand well with Lizzy. She has two versions now confronting her. Wickham's verbal account of Darcy and Darcy's authoritive yet intimate letter on events concerning Wickham. She reads the letter and re-reads it. Assesses it's claims, re-considers events, determines proabilities in relation to Wickham and Darcy then reconiles herself to the intial shock realization that Mr Wickham is not what he appeared. I don't think I'm saying anything you haven't already said. But your thoughtful post warranted more than a simple I agree. Line has adequately answered in relation to the etiquette of writing to a young woman outside the family. I almost wonder that Lizzy, a sensible young woman and well aware of decorum, did not refuse the letter. JA would have been well aware of such priorities. I wonder if it was remarked on by readers of her day? However, although Darcy took a risk how else could Wickham be revealed so that Lizzy alone could judge? JA seemed fond of utililizing letters as a literary device in her novels.