A film’s ending in French: Let It Be? (4)
I believe the answer is:
amen
'let it be?' is the definition.
('amen' means 'let it be' or 'so be it')
'a film's ending in french' is the wordplay.
'ending' says to take the final letters (the ending of the word).
'in french' becomes 'en' ('in' in French).
The final letter of 'film' is 'm'.
'a'+'m'+'en'='AMEN'
(Other definitions for amen that I've seen before include "Final word in prayer" , "prayer's ending" , "Conclusion of prayer" , "Word at the end of a prayer" , "Religiously 11 [THE LASTWORD]" .)