"Fake it till you make it" (also calle "act as if") is a common catchphrase that means to imitate confidence so that as the confidence produces success, it will generate real confidence. The purpose is to avoid getting stuck in a self fulfilling prophecy related to one's fear of not being confident, e.g., by thinking, "I can't ask that girl out because she would sense my lack of confidence." The article How You Too Can Be an Optimist in Prevention points out, "In research at Wake Forest University, for example, scientists asked a group of 50 students to act like extroverts for 15 minutes in a group discussion, even if they didn’t feel like it. The more assertive and energetic the students acted, the happier they were".