From Inside the Grey House:
Other than the fights about her training and her disappearances, the past year with her had been bliss. She was everything he could want in a woman: willing, adventurous, limber. She was also intelligent. She went through the books in his library asking for his help when she couldn’t read the language. Most of the books were first editions of classics, which she had read in school.
Natalia rearranged the books according to fiction and non-fiction, to make it easier to find the ones she considered useful. She integrated the Slayer journals as well, placing them in order by year started, showing Vincent the ones written about him. He enjoyed her company and found himself wanting to integrate her into his business life. First, he had to stop her from fighting. He was also annoyed that Natalia never apologized for her actions and her words. She simply went about doing her best to aggravate him.