Satisfy need at first in Tory depravity (8)
I believe the answer is:
convince
'satisfy' is the definition.
(I've seen this before)
'need at first in tory depravity' is the wordplay.
'at first' says to take the initial letters.
'in' is an insertion indicator.
'tory' becomes 'con' (abbreviation for conservative).
'depravity' becomes 'vice' (I've seen this before).
The initial letter of 'need' is 'n'.
'con'+'vice'='convice'
'n' put into 'convice' is 'CONVINCE'.
(Other definitions for convince that I've seen before include "Make believe" , "Satisfy by evidence" , "Be persuasive" , "Persuade someone of the truth of something" , "Win over to your point of view" .)