Butler included in a benefit that's lovely (8)
I believe the answer is:
adorable
'lovely' is the definition.
(synonyms)
'butler included in a benefit' is the wordplay.
'butler' becomes 'rab'.
'included in' means one lot of letters goes inside another.
'benefit' becomes 'dole' (I've seen this before).
'a'+'dole'='adole'
'rab' inserted into 'adole' is 'ADORABLE'.
'that's' is the link.
(Other definitions for adorable that I've seen before include "Very pleasing" , "Broad lea (anag.)" , "sweet" , "Evoking love and admiration" , "Loveable" .)