Governess made sure a mind's wasted (9)
I believe the answer is:
nursemaid
'governess' is the definition.
(thesaurus)
'sure a mind's wasted' is the wordplay.
'wasted' indicates anagramming the letters.
'sure'+'a'+'mind'='sureamind'
'sureamind' with letters rearranged gives 'NURSEMAID'.
'made' acts as a link.
(Other definitions for nursemaid that I've seen before include "One looking after children" , "Woman tending a child or children" , "tender" , "Be overprotective towards (someone)" , "Girl tending young children" .)