Though enchanting, she was never quite dear to me (5)
I believe the answer is:
medea
'though enchanting she was never quite' is the definition.
I can't tell whether this defines the answer.
'dear to me' is the wordplay.
'dear' becomes 'dea' (I am not sure about this - if you are sure you should believe this answer much more).
'to' means one lot of letters go next to another (I've seen this in other clues).
'dea' put after 'me' is 'MEDEA'.
Can you help me to learn more?
(Other definitions for medea that I've seen before include "Mythological Greek princess" , "Sorceress who helped Jason get the Golden Fleece" , "Mrs Jason" , "Tragedy by Euripides" , "Greek sorceress" .)