Yeah. There was even proof of it in the movie. When Haku was injured in the boiler room and Chihiro was planning to visit Yabuba's twin sister, Zeniba, Kamaji said " That's love" or something like that. When Chihiro was at Zeniba's house, she ( Zeniba) said that "I can't do anything to help that dragon boyfriend of yours." Sorry for the long description, I just really like them together.