Chizuru views him as "a professional" because they're making a movie together... even though he's donating his time and money and energy to help her, in exchange for not a single yen, with this very personal quest of hers -- and this is after more than a year of him paying her HUNDREDS OF DOLLARS a week (reminder that if you look back to their first date, he gave her 40,000 yen, which is $400 USD), meaning he's already given her more than $20,000 just because he likes to spend time with her.
How can she NOT think he likes her? She's literally a prostitute and this is her most lucrative customer