"I usually have responded to this with "you do not know what I am capable of"."
That's not the same as what I suggested. The words you stated sound weak as if you have something to prove to her. My words state a FACT and you don't care if she believes it or not.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.