Keeping doubt quiet at first (12)

I believe the answer is:

preservation

'keeping' is the definition.
(I've seen this before)

'doubt quiet at first' is the wordplay.
'doubt' becomes 'reservation' (reservation is a kind of doubt).
'quiet' becomes 'p' (music symbol for 'piano').
'at first' says to put letters next to each other.
'reservation' put after 'p' is 'PRESERVATION'.

(Another definition for preservation that I've seen is " Keeping".)

I've seen this clue in The Times.

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