What it means
Bona fide literally means "in good faith". In Australian legal practice it describes something genuine and honest, done without fraud or an ulterior motive — for example a bona fide purchaser who buys property honestly and without notice of any defect in title. The noun "bona fides" refers to a person's good faith or sincerity. Acting bona fide is often a requirement before the law will protect your interests, such as where good faith is needed to enforce a contract or claim certain property rights.
How it's used
The court accepted she was a bona fide purchaser who had no idea the seller never actually owned the car.