Endometriosis affects around 10% of women globally, yet the awareness and screening rates for this condition are relatively low. Utilizing an online survey-based experiment with a sample of 18–30-year-old young women (N= 326), this study aimed to investigate the efficacy of narrative messages vs. non-narrative messages for promoting endometriosis screening intention, as well as to evaluate the effectiveness of hope appeal vs. fear appeal in narrative messages. The study also examined the potential mediating mechanisms through self-efficacy and positive affect responses that may help elucidate the effect of emotional appeals on behavioral intentions, while taking into account an individual’s readiness to change. Findings indicated that narrative and non-narrative messages did not produce significantly different screening intentions. Compared to the use of fear appeal, the hope appeal in narrative messages predicted a higher level of positive affect responses, which was associated with increased endometriosis screening intentions. Individual difference in readiness to engage in endometriosis screening was not found to be a significant moderator. These results have implications for future research utilizing hope appeals in narrative health messaging. The observed significant mediational pathway through positive affect advances understanding of positive discrete emotions as facilitators to health-related cognition and behavior changes.