Ladies' champion in quest for a mate (6)
I believe the answer is:
knight
This clue is a double definition.
'ladies' champion' is the first definition.
(I've seen this before)
'in quest for a mate' is the second definition.
(I've seen this before)
(Other definitions for knight that I've seen before include "board member" , "He's a Sir in the UK" , "Ladies' champion" , "eg Elton John" , "Rank below baronet" .)