Advancements in science and technology have enabled communication beyond the constraints of time, distance, and physical limitations. In particular, the metaverse has facilitated interactions through avatars, and increasing attention is being given to “digital twins,” which are nearly identical digital replicas of real-world entities. Digital twins allow for simulations, future predictions, and iterative analyses that would otherwise be costly in the real world. Among these, “human digital twins” are particularly promising, with potential applications in personalized treatments based on individual characteristics, medical history, and real-time physiological data, as well as behavioral simulations. This study examines the potential application of human digital twin technology in interpersonal relationship-building. Establishing positive human relationships is crucial for well-being, contributing to reduced feelings of isolation and an improved quality of life. In first-time interactions, mutual self-disclosure is typically a key process in deepening relationships. Human digital twins, which can communicate through both verbal and non-verbal cues, may help reduce psychological barriers in initial conversations. In this research, we investigated whether watching a conversation between digital twins before an initial meeting influences relationship formation, using a Speed Dating scenario. The experimental results suggest that viewing digital twin interactions promotes psychological readiness before face-to-face meetings and helps establish a foundation for familiarity with the other person. This study demonstrates the potential of digital twin technology in facilitating interpersonal relationship-building and opens new possibilities for digital communication.