Terribly fast bee — certainly a winner (4,3)

I believe the answer is:

safe bet

I'm a little stuck... Click here to teach me more about this clue!

'certainly a winner' is the definition.
I can't tell whether this defines the answer.

'terribly fast bee' is the wordplay.
'terribly' indicates anagramming the letters.
'fast'+'bee'='fastbee'
'fastbee' anagrammed gives 'SAFE BET'.

Can you help me to learn more?

(Another definition for safe bet that I've seen is " Risk-free risk?".)

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