"I am full of hidden horrors!..."
See in text (The Medea)
By this Medea means that she is full of anger and hatred. She goes on to claim that she will relinquish this hatred and “forgive.” This is an instance of dramatic irony. While outwardly this sounds like a claim that Medea will change, the audience knows that this is in fact a reference to her murderous plot to kill Glauce, Creon, and her children.