Struggles of girl disheartened having entered wrong answer (8)
I believe the answer is:
wrangles
'struggles' is the definition.
(wrangle can mean a dispute or struggle)
'girl disheartened having entered wrong answer' is the wordplay.
'disheartened' means to remove the middle letters (the middle or heart is removed).
'having entered' indicates putting letters inside.
'wrong' indicates anagramming the letters.
'girl' with its centre removed is 'gl'.
'answer' with letters rearranged gives 'wranes'.
'gl' put within 'wranes' is 'WRANGLES'.
'of' is the link.
(Other definitions for wrangles that I've seen before include "Angry exchanges" , "Disputes" .)