Meanings of very impassiveness in English

His very impassiveness warned and steadied Johnny.

Her very impassiveness added to her charm; for who is there in this world who is not eager to learn a secret?

Hastening into the post office, he stood betraying his impatience by his very impassiveness while a sallow-faced woman tossed the letters out upon the counter.

"What the devil do you mean- "Butthe Jap's very impassiveness checked him and with an immense effort he regained command of himself.