Definition of Ethos
The novella makes use of ethos in the frame narrative when Douglas prefaces the tale he's about to tell. In doing so, he underlines the governess's authority by making her out to be a wonderful woman and—more importantly—not the sort of person who’s in the habit of randomly telling tall tales to strangers:
“I was much there that year — it was a beautiful one; and we had, in her off-hours, some strolls and talks in the garden — talks in which she struck me as awfully clever and nice. Oh yes; don’t grin: I liked her extremely and am glad to this day to think she liked me too. If she hadn’t she wouldn’t have told me. She had never told any one. It wasn’t simply that she said so, but that I knew she hadn’t. I was sure; I could see. You’ll easily judge why when you hear.”