Treat well, with a good result (4)

I believe the answer is:

cure

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'treat' is the definition.
(thesaurus)

I don't understand the remainder of the clue.

(Other definitions for cure that I've seen before include "Restore - kipper" , "priest without an accent" , "priest from 22 [ALSACE]" , "Heal or preserve" , "Make healthy, preserve" .)

I've seen this clue in the Evening Standard.

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