She was ruined by Ernie (5)
I believe the answer is:
irene
'she' is the definition.
(I've seen this before)
'ruined by ernie' is the wordplay.
'ruined by' indicates anagramming the letters.
'ernie' with letters rearranged gives 'IRENE'.
'was' is the link.
(Other definitions for irene that I've seen before include "US actress, -- Dunne" , "Goddess of peace - Byzantine ruler" , "Greek goddess of peace (English name)" , "Girl of peace" , "In Greek mythology, the goddess of peace" .)