Satisfaction guaranteed with request (8)
I believe the answer is:
pleasure
'satisfaction' is the definition.
(thesaurus)
'guaranteed with request' is the wordplay.
'guaranteed' becomes 'sure' (I've seen this in other clues).
'with' says to put letters next to each other.
'request' becomes 'plea' (plea is a kind of request).
'sure' put after 'plea' is 'PLEASURE'.
(Other definitions for pleasure that I've seen before include "Gratification of the senses" , "Feeling of enjoyment or satisfaction" , "A repulse (anag.)" , "Delight, happiness" , "contentment" .)