I figured that was what you means rather than using the term broader, but if that's the case, how does Ami, Noriko, Niki, and the Tsukiokas know, or what let them to thinking that he might? From what I remember Ami asked/gestured towards Sensei about whether or not he looked at her that way even back then, with him not confirming or denying it (maybe). Noriko only knows about him and Ami and that there are others, unless we're counting when Maya told Noriko "He chose me" as being evident that she knew of their relationship. But that confuses me because wasn't that about when Sensei left the second time?
Might have to go back through things.
Niki only knows (from my knowledge) that Sensei's done fucked up things before, via his own words. I recall a time where someone implied (or made a "what if" statement or something like that) about Sensei liking wizard age girls and Niki didn't take too kindly to it, but that's it. and as far as the Tsukiokas, Tsukasa is the one that keeps calling him her future husband but everyone else seems to just laugh it off. I could be missing something somewhere though.