Maverick (1957)

S1E3 According to Hoyle

Samantha Crawford, a skilled con artist, works for George Cross, who is intent on recouping the $50,000 he lost to Bret Maverick. Two riverboat proprietors back Maverick with $5,000, which he quickly loses to Samantha. She pretends that Cross is her father and claims she needs the money to bail him out of jail. In an effort to take down Joe Riggs, a corrupt game room owner, Maverick teams up with Samantha to buy gambling equipment. However, Samantha and Cross betray Maverick by selling the equipment directly to Riggs instead.