Musical token of affection cut short by opera house (6)
I believe the answer is:
'musical' is the definition.
'token of affection cut short by opera house' is the wordplay.
'token of affection' becomes 'kiss'.
'cut short' means to remove the last letter.
'by' is a charade indicator (letters next to each other).
'opera house' becomes 'met' (short for the Metropolitan Opera House in New York).
'kiss' with its final letter taken away is 'kis'.
(Other definitions for kismet that I've seen before include "Destiny; 50s musical", "Turkish fate, destiny", "Broadway musical", "Fate - 1953 musical", "lot in life".)