Accountant’s girl, one fated to be disbelieved (9)

I believe the answer is:

cassandra

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'one fated to be disbelieved' is the definition.
I can't tell whether this defines the answer.

'accountant's girl' is the wordplay.
'accountant's' becomes 'CA's' (abbreviation for chartered accountant).
'girl' becomes 'sandra' ().
'cas'+'sandra'='CASSANDRA'

Can you help me to learn more?

(Other definitions for cassandra that I've seen before include "one anticipating disaster" , "forecaster" , "was unbelievable" , "Person who prophesies disaster, after Greek legend (9)" , "destined to be disbelieved?" .)

I've seen this clue in The Times.

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