Y' know, I can totally imagine Mami suffeering a long, traumatic internal debate about the witchiness of Sabrina, and after one misadventure or another, she finally decides that she's OK with it as long as Sabrina remains Sabrina as she knows her, and confidently and reassuringly confides her resolution to Sabs...
Player Sabrina:
A) Uh... I'm not actually a Witch... Thanks, though! That means a lot to me.
B) But I'm not... I mean I think... maybe, uh... [EXISTENTIAL CRISIS]
C) ... Admit it. You're totally a Witch, and you're glad Mami accepts you as such (totally not accepting just to avoid complicating things further now that an (in)correct resolution was found, what are you talking about).
D) "Oh, Mami."