Unexpectedly cured, Anne shows stamina (9)
I believe the answer is:
endurance
'stamina' is the definition.
(I've seen this in another clue)
'unexpectedly cured anne' is the wordplay.
'unexpectedly' is an anagram indicator.
'cured'+'anne'='curedanne'
'curedanne' is an anagram of 'ENDURANCE'.
'shows' is the link.
(Other definitions for endurance that I've seen before include "Patient toleration" , "Ability to stay a difficult course, courage" , "Power to withstand hardship or stress" , "Tenacity" , "Staying power" .)