Sing in French first to delight (7)
I believe the answer is:
enchant
'delight' is the definition.
(enchanting is a kind of delighting)
'sing in french first' is the wordplay.
'sing' becomes 'chant' (chanting is a kind of singing).
'in french' becomes 'en' ('en' can be French for 'in' e.g. en France).
'first' is a charade indicator (letters next to each other).
'chant' after 'en' is 'ENCHANT'.
'to' is the link.
(Other definitions for enchant that I've seen before include "Delight, charm" , "Appeal" , "Captivate, charm" , "Delight or bewitch" , "Delight, cast spell over" .)