Midrasz do Powtórzonego Prawa 25:12

And whence is it derived that one who shamed another pays money? It is written here (19:21) "your eyes shall not pity," and elsewhere (in an instance of shaming) (Ibid. 25:12) "your eyes shall not pity." Just as here monetary payment (is being referred to), so, there, monetary payment.

(Devarim 25:12) "Then you shall cut off her hand": We are hereby taught that you are obligated to rescue him (from her). Whence is it derived that if you are not able to rescue him by (cutting off) her hand, you must rescue him by her soul (i.e., by killing her)? From "you shall have no pity."