Most pleasing convert in sect (6)
I believe the answer is:
nicest
'most pleasing' is the definition.
(I've seen this before)
'convert in sect' is the wordplay.
'convert' is an anagram indicator (I've seen this in other clues).
'in'+'sect'='insect'
'insect' is an anagram of 'NICEST'.
(Other definitions for nicest that I've seen before include "Most pleasant or fine" , "Most appealing" , "Most attractive" , "Best" , "I scent in the most pleasant way" .)