Abigail's body language communicates that she cleaves to the trust that Danforth has had for her, and that she shows suspicion of others, namely Proctor.
Her specific answer to Danforth is this:
If I must answer that, I will leave and I will not come back again!
Through gesture and dialogue, Abigail's character portrays that she thinks she is in charge of these circumstances. This is strange because she is just a teenager still, not the presiding Judge. Furthermore, Abigail never directly answers Danforth with a 'yes' or 'no'. So far, everyone else has had to answer Danforth until he is satisfied with his line of questioning. Abby seems to have special privileges. When Abby speaks again to Danforth after this line, he makes an attempt to put her in her place, but it is rather weak.