She sounds optimistic (5)
I believe the answer is:
rosie
'she' is the definition.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for rosie that I've seen before include "Girl's name" , "Old song: 'Sweet ..... O'Grady'" , "Female" , "Cider with - (Laurie Lee)" , "- - Lee (sl.)" .)