Struggle to be found in a belief for this work (6)
I believe the answer is:
effort
'struggle' is the definition.
(I've seen this before)
'found in a belief for this work' is the wordplay.
'found in' says the answer is hidden in the clue.
'EFFORT' is hidden in the letters of 'belief for this work'.
'to be' acts as a link.
(Other definitions for effort that I've seen before include "Strain" , "The use of physical or mental energy" , "Strenuous endeavour" , "An exertion of energy" , "Hard mental or physical work" .)