Girl disheartened for very long time (4)
I believe the answer is:
ages
'very long time' is the definition.
(I've seen this in another clue)
'girl disheartened' is the wordplay.
'girl' becomes 'Ag'.
'disheartened' becomes 'es' (I can't explain this - if you can you should believe this answer much more).
'ag'+'es'='AGES'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for ages that I've seen before include "Times" , "Gets older" , "Donkey's years" , "Sage (anag)" , "Historical eras" .)