You do not believe she is truly repentent. "Apologize to your sister, too. You have offended her. That will be a better sign of your repentance than an apology only to me." You wait for her reply.

Nabiki stares at you for a moment. "Perhaps you are smarter than I thought." She turns to Akane. "I am sorry, and I will not do it again until I need the money."

Akane groans, "That's not much of an apology."

Nabiki says, "Would you rather I lie to you?"

Akane says, "Hmm... I guess that is the best apology I will get." She turns and leaves.