Despair a change in the garden (8)
I believe the answer is:
paradise
'garden' is the definition.
(thesaurus)
'despair a change' is the wordplay.
'change' is an anagram indicator.
'despair'+'a'='despaira'
'despaira' with letters rearranged gives 'PARADISE'.
'in the' is the link.
(Other definitions for paradise that I've seen before include "Poem by 1" , "Elysian fields" , "Utopia" , "Persian word which in Hebrew became 'a blessed place'" , "Place of utter bliss" .)