Find out sectarian is corrupt (9)

I believe the answer is:

ascertain

'find out' is the definition.
(I know that find out can be written as ascertain)

'sectarian is corrupt' is the wordplay.
'is corrupt' is an anagram indicator (a corrupt or distorted order of the letters).
'sectarian' is an anagram of 'ASCERTAIN'.

(Other definitions for ascertain that I've seen before include "Find out for sure, determine" , "settle" , "Prove" , "Establish after an investigation or study" , "Learn" .)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app