The cost of undertaking a serious accusation? (5,6)

I believe the answer is:

grave charge

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'the cost of undertaking a' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'serious accusation?' is the wordplay.
'serious' becomes 'grave' (both can mean solemn).
'accusation?' becomes 'charge' (accusation is a kind of charge).
'grave'+'charge'='GRAVE CHARGE'

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I've seen this clue in The Globe and Mail.

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