Abstract. Background: High school and university teachers need to advise students against attempting suicide, the second leading cause of death among 15–29-year-olds. Aims: To investigate the role of reasoning and emotion in advising against suicide. Method: We conducted a study with 130 students at a university that specializes in teachers' education. Participants sat in front of a camera, videotaping their advising against suicide. Three raters scored their transcribed advice on "wise reasoning" (i.e., expert forms of reasoning: considering a variety of conditions, awareness of the limitation of one's knowledge, taking others' perspectives). Four registered psychologists experienced in suicide prevention techniques rated the transcripts on the potential for suicide prevention. Finally, using the software Facereader 7.1, we analyzed participants' micro-facial expressions during advice-giving. Results: Wiser reasoning and less disgust predicted higher potential for suicide prevention. Moreover, higher potential for suicide prevention was associated with more surprise. Limitations: The actual efficacy of suicide prevention was not assessed. Conclusion: Wise reasoning and counter-stereotypic ideas that trigger surprise probably contribute to the potential for suicide prevention. This advising paradigm may help train teachers in advising students against suicide, measuring wise reasoning, and monitoring a harmful emotional reaction, that is, disgust.