of him/her; on his/her part
Un tel comportement de sa part est impardonnable.
Such behavior on his part is unforgivable.
Ce que tu me dis est complètement différent de ce que j'ai entendu de sa part.
What you're telling me is completely different from what I heard from him.
S'il meurt, ce ne sera pas chic de sa part.
If he dies, it won’t be very nice of him.
— Quand passent les cigognes (1957)
C'est adroit de sa part de résoudre un problème si difficile.
It was clever of him to solve such a difficult problem.
C'était impoli de sa part d'agir ainsi.
It was rude of him to act that way.
Jusqu'à ce jour, nous n'avons obtenu aucune réponse de sa part.
To this day, we have received no response from him/her.
Mais il savait aussi que l'on pouvait s'attendre à tout de sa part.
But he also knew that you could expect anything from him.
That's kind of him.
C'était négligent de sa part de faire une telle erreur.
It was careless of him to make such a mistake.