When you come out on top, certain to be charming (7)
I believe the answer is:
winsome
'be charming' is the definition.
(I've seen this before)
'when you come out on top certain' is the wordplay.
I cannot really see how this works, but
'certain' could be 'some' (synonyms) and 'some' is found within the answer.
'come out on top' could be 'win' (I've seen this in another clue) and 'win' is found in the answer.
No letters remain.
This explanation may well be incorrect...
'to' is the link.
Can you help me to learn more?
(Other definitions for winsome that I've seen before include "Holding an appeal" , "Fetching" , "Pleasant" , "Charming, engaging" , "Captivating" .)