I mean really look like?
Beliefs dictate behaviour. For instance, a person who truly believes his home is haunted is probably going to have a lot of sleepless nights imagining every knock and bump to be a supernatural visitation. A person who truly believes the police are after her might act in an extremely paranoid manner, imagining telephone taps, undercover detectives and the like.
So how can we be reasonably confident that most people who say they believe in Heaven or the equivalent aren’t actually as secure in their belief as they claim?