Don't confess to any murders up front. Start small, wait for people to reciprocate. If they do, escalate. This is actually a mild formula for building deeper friendships. Arthur Aaron made people feel like lifelong friends in under an hour just by revealing things about themselves. Two of the research associates that he had on it ended up getting married.
Eric Barker teaches our curator Daniel Pink how to make friends, disarm marital conflicts, and spot liars.