He can't be trusted after a deal is made (9)

I believe the answer is:

cardsharp

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'he can't be trusted after a deal is made' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.

'he can't be' is the wordplay.
'he' becomes 'Car'.
'can't be' becomes 'dsharp' (I can't justify this - if you can you should believe this answer much more).
'car'+'dsharp'='CARDSHARP'

Can you help me to learn more?

(Other definitions for cardsharp that I've seen before include "One who cheats with a pack" , "Cheater at the table" , "Dodgy dealer" , "Cheater at, say, poker" , "cheat" .)

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

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