Before changing the narration, optative sentences are first converted to assertive sentences.
"How pretty you are!" said the fox to the crow. "I am sure so beautiful a bird must have a beautiful voice. Cheer up, my dear, will you not sing a few notes for me?"

Explanation

The fox flattered the crow saying that he was very pretty and told him that she was sure that so beautiful a bird must have a beautiful voice. She cheered him up lovingly and asked him if he would not sing a few notes for her.