He was a gentleman to her. He showed her kindness and consideration from the beginning, and made it clear he respected her as an equal, respected her intelligence, her expertise, respected her as a person. He also made it clear he was interested in her without being forceful or making it awkward, which is a very sexy move.

For his interest in her, it's a no-brainer. She's a smart, warm, emotionally mature, attractive, kind and well mannered person. He'd be silly not to want her.

I guess I can see their chemistry, apart from the attraction they share, to come from the same place of treating each other well. Anna came from an abusive home and it doesn't seem like she had many tender experiences with men after that. For John, he and his ex wife had a toxic relationship where it seems she was the main abuser- Bates does some questionable things as a husband at times, and makes some pretty bad decisions, but he never abuses Anna and always puts her first. They're there for each other and care for each other in ways no one else has done for either of them before. I think overall their relationship is sweet and works well, even though the characters and their storylines can be tedious at times (especially Bates).