This study aims to explore how elementary school teachers interpret and respond to students’ emotional reactions when teaching “difficult histories” in the classroom. Using a qualitative case study design, the research analyzes teacher interview data through three theoretical lenses: Britzman’s (1998) concept of the “otherness of knowledge,” Britzman and Pitt’s (2003) notion of “lovely knowledge,” and Kang Sun-joo’s (2023) concept of the “correlativeness of knowledge” to illuminate how students experience emotional confusion, retreat into familiar narratives, or remain silent to preserve social relationships when confronting “difficult histories”. The findings show that the “otherness of knowledge” emerged as students encountered shock, avoidance, or guilt when learning about topics such as the Japanese military “comfort women” and the May 18 Democratic Uprising. “Lovely knowledge” appeared when preexisting biases toward Japan, North Korea, or China, and teachers’ protective emotional strategies, simplified complex histories into emotionally agreeable narratives. The “correlativeness of knowledge” was evident when students conformed to dominant sentiments or self-censored to avoid relational risks in discussions of reunification, war, or colonialism. These findings indicate that learning “difficult histories” encompasses emotional and relational dimensions beyond cognitive understanding. Teachers must design learning environments that transform emotions into critical engagement, ensure emotional safety, and reconstruct historical narratives in ways that preserve both otherness and relationality.