Willoughby’s uncharacteristic departure gives the residents of Barton Cottage an unhappy jolt. In Ch. 15 his deceptiveness, his unwillingness to admit a return or accept an invitation from Mrs. Dashwood upsets the lady so much her reaction is to defend him and scold dear Elinor for suspecting him.

"Yes. I have explained it [Willoughby’s behavior] to myself in the most satisfactory way; -- but you, Elinor, who love to doubt where you can -- -- It will not satisfy you

Oh! Elinor, how incomprehensible are your feelings! You had rather take evil upon credit than good. You had rather look out for misery for Marianne and guilt for poor Willoughby, than an apology for the latter.

I think Mrs. Dashwood mischaracterizes Elinor’s desire for evidence of Willoughby’s intentions because she had doubts herself and does not like questioning what she has assumed to be true. I guess it would be a terrible feeling to have doubt suddenly thrust upon you about a subject you were positive you understood completely. However, I cannot approve of her scolding Elinor. The “It will not satisfy you” especially seems to blame Elinor for not feeling as she does.

Oh, I am an Elinor fan! (:D)