References in classic literature ?
Yes; for Arthur was at ease about Hetty--not quite at ease about the past, for a certain burning of the ears would come whenever he thought of the scenes with Adam last August, but at ease about her present lot.
In her memories of Vronsky there always entered a certain element of awkwardness, though he was in the highest degree well-bred and at ease, as though there were some false note--not in Vronsky, he was very simple and nice, but in herself, while with Levin she felt perfectly simple and clear.
His legs were weary, but his mind was at ease, free from the presentiment of change.