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.
(..) for as long as I can remember. Everyone's always asking me to believe in things... family, gods, kings, myself. It was often tempting until I saw where belief got people. So I said no, thank you to belief. And yet here I am. I believe in you. It's embarrassing, really. I'd swear you my sword, (..)2016 TvShow: Game of Thrones Title: The Winds of Winter Season: 6 Episode 10