Who is the person offering to help Buffy?

A vampire (Yes, you read that correctly)

"Who are you?" asked Laurel of the dark-haired woman in a black dress who sat at the back of the dining room. The woman was sitting next to a tall, white-haired gentleman who was wearing a black leather coat and she seemed to have an intense look upon her face that Laurel could not quite read.

"My name is Messalina," said the woman. "I could not help overhearing your dilemma and I would like to help."

"What can you do?" asked Sir Roderick.

"My boyfriend, Stake, here says that I have a gift for what you might call hypnotherapy," said Messalina. "I've used it to calm down many an angry suitor in my day and I might be able to use the same gift to help your dragon slayer. After all, at the end of the day, her problem is not that she cannot do her job. It is that she is afraid to try."

"Of course I'm afraid to try," said Buffy. "I'm going to die out there if I try."

"No, you won't," said Messalina. "I once knew a girl named Niccola Wood who had the same concerns about fighting a dragon in the rain that you do and things worked out just fine for her. In fact, you remind her a bit of her. Not that you two have that much in common physically but personality-wise... Yes, I would like to help you the same way I helped Niccola. If you'd let me."

"Are you saying that Niccola Wood was a dragon slayer just like me -- and that everything worked out okay for her?" asked Buffy.

Messalina replied, "That's one way to put it."