The unhinged witch realized in this moment just how smart Hermione truly was and that she may even be evenly matched by this girl. It horrified her, but naturally made her admire the moment. "so, what do we do" Bellatrix spoke bluntly. Wanting this conversation to end, quickly. Hermione stood for a moment. "you confess to her." Not at all the reaction she was expecting, but after a quick thought she realized that Hermione actually wanted her to confess to see if her sister would stay, to see if Bellatrix was right and if it really wouldn't effect their relationship. More then anything, if Narcissa was infuriated, then she would be able to obtain some revenge for feeling played.