The Mark of the Renegade (1951)

In 1825 Marcos Zappa is blackmailed by Don Pedro Garcia, whose ambition is to be emperor of California. Garcia schemes to have Marcos seduce and marry Manuella, the daughter of his rival, Jose De Marquez. Manuella, who is already engaged to be married to Miguel De Gandara, is attracted to Marcos but not sure if she should trust him.