Hopelessness of French husband and wife (7)
I believe the answer is:
despair
'hopelessness' is the definition.
(despair is a kind of hopelessness)
'of french husband and wife' is the wordplay.
'of french' becomes 'des' (I've seen this in other clues).
'husband and wife' becomes 'pair' (I've seen this before).
'des'+'pair'='DESPAIR'
(Other definitions for despair that I've seen before include "Give up hope" , "Praised (anag) - lose hope" , "Opposite of 10" , "displaying lack of optimism" , "The feeling that nothing will turn out well" .)