Many people arrived early 'in the mistaken/erroneous belief that' [=because they mistakenly believed that] free tickets would be available.
It's my 'belief that' the current policy is certain to fail. [=I believe that the current policy is certain to fail]
There is a 'growing belief that' [=an increasing number of people believe that] these policies will not succeed.
(..) And that's how we get hamburgers Now chickens! Only you who can save her, Drake! Damn it! I'm a doctor. I'm not God! There goes my whole belief system. It's Erika. Quick! Shut off the TV. I wanna see what happens! I get Leslie out of the coma then we make out. (..)1996 TvShow: Friends Title: The One After the Superbowl: Part 1 Season: 2 Episode 12