It's kind of a running joke with both women, Yor is a highly dangerous woman and generally caring person (In part because she had to take care of her brother, although he's barely in the movie) but kind of clueless when it comes to social interactions and relationships.
Nightfall is just obsessed as well.
Although the movie did explain a lot in the narration, it kind of left out that part of Yor's backstory and Nightfall.
The City Hunter netflix live-action Japanese movie came out today, getting mixed reviews.