The present study, using a qualitative approach and thematic analysis method, examines students' lived experiences of choosing and studying at Kosar single-sex university. Twelve undergraduate and graduate students in the faculties of humanities, basic sciences, and technical and engineering were selected as the study sample using purposive sampling. Data were collected through semi-structured interviews and analyzed using thematic analysis. Five main themes (students' individual motivations; the impact of family and social factors; students' interpretations of the single-sex space; institutional characteristics of the university; and the long-term impact of choosing a single-sex university) were identified as factors affecting university choice, which indicate that the choice is formed in a three-stage process: adaptation, challenge, doubt, and revision, which ultimately creates a complex sense of growth accompanied by regret in students. Therefore, studying at a single-sex university is a journey with dual emotions for students, who are always fluctuating between a sense of comfort in a friendly space and the limitations caused by a single-sex space. It is suggested that educational policymakers strengthen the balance between the sense of security and social readiness to enter mixed communities in such an space by improving mixed socialization facilities and programs.