...I didn't want to mention the "r" word, but did Willoughby - shall we say, force himself on her? Remember, she was unprotected. Assuming he did - and yes, it is an assumption, because there appears to be no direct evidence to support it - it certainly throws all that episode of his "confession" into a much darker light. In short, he would be lying to Elinor. If he lies about this, he would certainly be capable of lying about other things. In other words, his testimony about anything that can't be independently verified would be suspect.

Of course, this is an extreme scenario, and therefore mere speculation (although I'll flatter myself by calling it "thought-provoking" rather than "idle"). But doesn't this raise the question of exactly what was in Eliza's letter that forced Colonel Brandon to depart Barton at a moment's notice in Ch.13? Could she have said that she was raped, something that would be kept so "hushed up" that Willoughby could afford to lie about it to a third party and get away with it?