He's helping her, he's floating her over, by kindness." Maria rather funnily considered it.

"Floating her over in champagne?
The kindness of dining her, nose to nose, at the hour when all Paris is crowding to profane delights, and in the--well, in the great temple, as one hears of it, of pleasure ?" "That's just IT, for both of them," Strether insisted--"and all of a supreme innocence.

The Parisian place, the feverish hour, the putting before her of a hundred francs' worth of food and drink, which they'll scarcely touch--all that's the dear man's own romance; the expensive kind, expensive in francs and centimes, in which he abounds.
And the circus afterwards--which is cheaper, but which he'll find some means of making as dear as possible--that's also HIS tribute to the ideal.

It does for him.

He'll see her through.