Settled a selfish desire (6)
I believe the answer is:
agreed
'settled' is the definition.
(settled can mean agreed or decided)
'a selfish desire' is the wordplay.
'selfish desire' becomes 'greed' (I've seen this in another clue).
'a'+'greed'='AGREED'
(Other definitions for agreed that I've seen before include "Accorded" , "admitted" , "Acquiesed, concurred" , "Concurred - tallied" , "I'll go along with that" .)