A wide friendship network helps us in our daily lives, and there are merits to expanding personal connections. Newly developed communication services have been developed as a means to expand the network of connections, and they enable the building of new relationships on the Internet without meeting people directly. While these tools are spreading, currently in Japan, various warnings and instructions are communicated regarding Internet encounters, and due to interactions of young people via the Internet, many people recognize that it is dangerous to have relationships with unknown partners. We want to alleviate the distrust users have for unknown partners and contribute to relationship-building on the Internet. This paper proposes ComFriends, a communication tool that reduces the resistance of an initial conversation and helps expand friendships more easily and safely. ComFriends provides users with conversations between people who belong to the same community and are in a state of mutual interest, and it supports relationship-building. We first present a ComFriends design approach and then describe its evaluation via a user study.