Emphatically hoping for children to change sides (6)
I believe the answer is:
bloody
'emphatically' is the definition.
Both the definition and answer are adverbs. Perhaps there's a link between them I don't understand?
'hoping for children to change sides' is the wordplay.
I cannot really understand how this works, but
'change' could be 'blood' (blood is a kind of change) and 'blood' is present in the answer.
A single letter 'y' remains which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
(Other definitions for bloody that I've seen before include "Cruel, murderous" , "Gory" , ""____ but unbowed"" .)