Sentence:  "You'll never get her over like that. You must coax her." / "Coax the devil. Do you think I'm going to be beat by a horse?" / "It would only be <WSD>tit for tat</WSD>; you beat her, so she has a right to beat you." 
Meaning of the word marked with <WSD> tags:  Equivalent retribution; an act of returning exactly what one gets; an eye for an eye.