Imagine this "tall, imposing woman" is, instead, barrel-chested and vigorous man, strutting into the room like he owns the place.
"Bowers opened the door of the reception room and a tall, imposing woman rustled in, bringing with her a glow of animation which pervaded the room as if half a dozen persons, all talking gaily, had come in instead of one.
"She was large, handsome, expansive, uncontrolled; one felt this the moment she crossed the threshold.
"She shone with care and cleanliness, mature vigor, unchallenged authority, gracious good-humour, and absolute confidence in her person, her powers, her position, and her way of life; a glowing, overwhelming self-satisfaction, only to be found where human society is young and strong and without yesterdays."
This passage is from Song of the Lark by Willa Cather. I know this person, but as I said, it is a man. His humor is far from "gracious," but otherwise the description fits. I wonder if the rest of the story will provide insight if I keep reading.