It enchanted him.
As he proclaimed to the table, she had "a way with her." She had, indeed, as Roscoe Sheridan, upon her right, discovered just after the feast began.

Since his marriage three years before, no lady had bestowed upon him so protracted a full view of brilliant eyes; and, with the look, his lovely neighbor said--and it was her first speech to him-- "I hope you're very susceptible, Mr.Sheridan!" Honest Roscoe was taken aback, and "Why ?" was all he managed to say.
She repeated the look deliberately, which was noted, with a mystification equal to his own, by his sister across the table.

No one, reflected Edith, could image Mary Vertrees the sort of girl who would "really flirt" with married men--she was obviously the "opposite of all that." Edith defined her as a "thoroughbred," a "nice girl"; and the look given to Roscoe was astounding.

Roscoe's wife saw it, too, and she was another whom it puzzled--though not because its recipient was married.
"Because!" said Mary Vertrees, replying to Roscoe's monosyllable.

"And also because we're next-door neighbors at table, and it's dull times ahead for both of us if we don't get along." Roscoe was a literal young man, all stocks and bonds, and he had been brought up to believe that when a man married he "married and settled down." It was "all right," he felt, for a man as old as his father to pay florid compliments to as pretty a girl as this Miss Vertrees, but for himself--"a young married man"-- it wouldn't do; and it wouldn't even be quite moral.