From ONUV, only wins if the Assassin dies
If the Assassin is not in play then the Apprentice Assassin’s strategy resolves to that of the Assassin.
If the Assassin has not been outed then the Apprentice Assassin can claim to be another Team Village role and claim to have deduced that the Assassin is a Vampire. The more subtly that she can do this the better. The Assassin will be stuck in a bind since he can’t really refute this convincingly without outing himself as the Assassin. He might only out himself as the Assassin as a last resort if he sees his lynching becoming a near certainty, but by then it will probably be too late.
If the Assassin has been outed then the Apprentice Assassin’s best bet is probably to out herself as the Apprentice Assassin, announce that she’s going to vote for the Assassin and encourage any Vampires to follow her. This allows the Vampires and Apprentice Assassin to focus their votes on a single non-vampire player, thus solving the Vampire’s problem of coordinating and focusing votes without exposing themselves.
What do you think? Leave your thoughts in the comments section.