The number one, foolproof, sure-fire way to tell if someone is worthy or not is to start a hard conversation with them. If they are acknowledging and respectful, even when there is conflict, they will always be so. One does not need to know a person any length of time to do this. Call people out on their bullshit on day one, politely and intelligently, and take note of how they re/act. Waiting around is just wasting time.