How can I get Pyotr out of the bar?

Hint 1 of 14:

You might want to ask the butler at the castle.

Hint 2 of 14:

If you irritate him, he'll just leave.

Hint 3 of 14:

There's a sore subject in his life.

Hint 4 of 14:

Talk to him a few times, and you'll learn about Sasha.

Hint 5 of 14:

You'll also find something that reminds him strongly of her.