Changing sides, beggar becomes more hopeful (8)
I believe the answer is:
brighter
'more hopeful' is the definition.
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for brighter that I've seen before include "Sunnier or smarter" , "Cleverer" , "Emitting more light" , "More sunny" , "More brilliant" .)