Uncertain about arranged dates or absolutely sure? (4-6)

I believe the answer is:

rock-steady

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'absolutely sure?' is the definition.
I can't tell whether this definition defines the answer.

'uncertain about arranged dates' is the wordplay.
'uncertain' becomes 'rocky' (I've seen this in another clue).
'about' means one lot of letters goes inside another.
'arranged' indicates anagramming the letters (letters rearranged).
'dates' anagrammed gives 'stead'.
'rocky' enclosing 'stead' is 'ROCK-STEADY'.

'or' acts as a link.

Can you help me to learn more?

(Other definitions for rock-steady that I've seen before include "Absolutely stable" , "Never deviating" .)

I've seen this clue in The Independent.

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