Emotional forecasting is an important psychological process through which individuals predict future emotional experiences and use these expectations to guide decisions, motivation, and behaviour. In achievement contexts, particularly among young adults, anticipated emotional responses following unexpected performance failure may influence whether individuals continue pursuing goals or disengage from future challenges. Although previous research has examined affective forecasting errors and achievement motivation separately, the relationship between emotional forecasting accuracy and persistence after unexpected failure requires further investigation. This systematic review synthesizes existing evidence on emotional forecasting accuracy and persistence following unexpected performance failure among young adults. The review integrates findings from affective psychology, cognitive psychology, educational psychology, motivation research, and behavioural science to examine differences between anticipated and experienced emotions and their influence on future goal-directed behaviour. A structured systematic review methodology was applied to identify, evaluate, and synthesize relevant studies focusing on emotional prediction, achievement failure, emotional regulation, self-efficacy, resilience, and persistence. The findings indicate that emotional forecasting accuracy is influenced by cognitive appraisal, perceived importance of outcomes, previous experiences, coping strategies, and individual differences in emotional regulation. Evidence suggests that unexpected performance failure does not necessarily result in long-term disengagement; rather, persistence depends on how individuals interpret failure, regulate emotional responses, and evaluate their ability to recover and improve. Young adults often anticipate stronger negative emotions than they ultimately experience because they underestimate psychological adaptation processes. This review highlights emotional forecasting as a dynamic process involving prediction, emotional adaptation, and behavioural regulation, providing theoretical and practical implications for educational interventions, psychological support programs, and resilience-building approaches.