Insouciance

Definition: state of nonchalance or indifference

It’s French for “not anxious”

Why I Looked It Up

From Information Hunters:

To the men who had been in distant outpoints, Paris was a wonder. Eating real meals, taking in shows, and strolling the streets, they marveled at the beauty and insouciance of the city.

Not quite sure of the meaning there, honestly.