Terrible heartless sins nutter commits (8)
I believe the answer is:
entrusts
'commits' is the definition.
('entrust' can be a synonym of 'commit')
'terrible heartless sins nutter' is the wordplay.
'terrible' is an anagram indicator.
'heartless' means to remove the middle letters.
'sins' with its middle removed is 'ss'.
'ss'+'nutter'='ssnutter'
'ssnutter' is an anagram of 'ENTRUSTS'.
(Other definitions for entrusts that I've seen before include "Puts into the care or protection of" , "Gives into the care of" , "Places in a person's safe care" , "Willingly gives responsibility to" , "Commits confidently to another." .)