Very good to shine, fast (9)
I believe the answer is:
excellent
'very good' is the definition.
(I've seen this before)
'shine fast' is the wordplay.
'shine' becomes 'excel' (I've seen this in another clue).
'fast' becomes 'lent' (Lent is a period of fasting in Christianity).
'excel'+'lent'='EXCELLENT'
'to' is the link.
(Other definitions for excellent that I've seen before include "Great!" , "'Superior, first class (9)'" , "magic" , "brilliant" , "Admirable, first-rate" .)