Who is the "willowy woman waited" on the last page of A Gentleman in Moscow?

Spoiler alert! The willowy woman with the graying hair at the end of the book is none other than Anna, Count Rostow's actress girlfriend. In relation to a person, "willowy" means tall and slim, and that's precisely how Anna's been described on numerous occasions right throughout the book.
What's significant about the final action of the book is that the count has made the fateful decision to stay in the Soviet Union with Anna despite the fact that, as an aristocrat and therefore a "class traitor," he is technically an enemy of the state. The count could've remained in Paris along with many other Russian émigrés; at least there, he would've been safe from the revolutionary authorities. But the pull of his homeland is ultimately too strong for him to resist, and so he and the willowy Anna commit themselves, for good or ill, to live and die in Mother Russia.