She was there to keep him quiet--it was Amerigo's own description of her influence; and it would only have needed a more visible disposition to unrest in him to make the account perfectly fit.
Fanny herself limited indeed, she minimised, her office; you didn't need a jailor, she contended, for a domesticated lamb tied up with pink ribbon.

This was not an animal to be controlled--it was an animal to be, at the most, educated.

She admitted accordingly that she was educative--which Maggie was so aware that she herself, inevitably, wasn't; so it came round to being true that what she was most in charge of was his mere intelligence.

This left, goodness knew, plenty of different calls for Maggie to meet--in a case in which so much pink ribbon, as it might be symbolically named, was lavished on the creature.
What it all amounted to, at any rate, was that Mrs.Assingham would be keeping him quiet now, while his wife and his father-in-law carried out their own little frugal picnic; quite moreover, doubtless, not much less neededly in respect to the members of the circle that were with them there than in respect to the pair they were missing almost for the first time.

It was present to Maggie that the Prince could bear, when he was with his wife, almost any queerness on the part of people, strange English types, who bored him, beyond convenience, by being so little as he himself was; for this was one of the ways in which a wife was practically sustaining.