Ingratiate oneself (5,6)
(Other definitions for curry favour that I've seen before include "toady" , "Bow and scrape" , "Seek to ingratiate oneself" , "Suck up" .)
'ingratiate oneself' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for endear that I've seen before include "Make attractive or lovable" , "Make appeal" , "Charm, captivate" , "Make loveable" , "Make love" .)