Like Gen Z, Billie Jean King says manifesting really works: ‘If you think you’re a failure, you’ll fail. If you think you’re a winner, you’ll win’

• Gen Z might be on to something when they say manifesting and having a “delulu” mindset—that is, having an almost irrational belief in yourself—is the secret to success. That’s because tennis legend Billie Jean King says that the top 1% of professionals preach positivity to themselves. “If you think you’re a failure, you’ll fail. If you think you’re a winner, you’ll win,” she tells Fortune.

Chances are, after losing out on a big pitch, job interview, or—in Billie Jean King’s world—a tennis match...