Many a time beset by evil -- good to be mollifying (9)
I believe the answer is:
softening
'be mollifying' is the definition.
(thesaurus)
'many a time beset by evil good' is the wordplay.
'many a time' becomes 'often'.
'beset by' means one lot of letters goes inside another ('beset' could historically mean 'cover').
'evil' becomes 'sin' (I've seen this before).
'good' becomes 'g' (abbreviation).
'often' going within 'sin' is 'softenin'.
'softenin'+'g'='SOFTENING'
'to' is the link.
(Other definitions for softening that I've seen before include "Cushioning" , "becoming more lenient" .)