1. Lack of confidence: Worried that one's performance may not attract the other person, or afraid that one's words and actions will make the other person feel uncomfortable.
2. Social anxiety: When alone with the opposite sex, one may feel nervous and uneasy, worried that they may not be able to cope with the awkward situation that may arise.
3. Past experiences: may have had unpleasant experiences with the opposite sex, leading to fear and resistance towards being alone with the opposite sex.