Testifying at a preliminary hearing, the victim, Tim, said he began buying cars and other gifts for Belinda Mitchell in 1999, after she promised to marry him.
He also gave her tens of thousands of dollars for purported cancer treatments, Tim said. His last name is being withheld at his request.
Mitchell, 36, and her husband, Richard, 34, were arrested this summer after Tim, suspecting a scam, went to police.
The hearing is being held before a Sacramento Superior Court judge who will decide whether to order a trial for the Mitchells, who are charged with conspiracy and unlawfully taking money and property.
The couple, who have denied the allegations, are being held in the Sacramento County jail. The hearing is to resume today.