About to reply in the affirmative, Emma changes her mind at the last minute. "...What are the rules of magic where you're from? What's the 'usual way'?"

Best to know what's she getting into by replying.

...What if she has to give up her soul? Or go back to Hell with him? He's a demon! She doesn't know how this works.

Someone in the back of the class calls out an extremely inappropriate suggestion. Emma turns bright, bright red. For lack of a response (that she could make in front of a professor), she ignores them entirely.