On the novel at this point he really was assume Anze as a pr*stitue, and beside investigation(of someone stole his data) he was kinda expecting what Anze do after they go inside the apartment.
When this revealed very later on, Anze ask "what if he turn out innocent, and he really trying to seduce him?", his answer was implying he's likely not gonna refuse.
This was rather surprising because so out of his character. The only logical explanation was the arbiter already fascinated by Anze on their very first meeting.
Iirc Apparently that magic stone's value is tens of billions