FYI that is a misleading statement of Critical Rationalism.

For one thing, Popper was not a "belief philosopher" so he wouldn't have stated it quite like that.

There are a lot of misleading statements about CR floating around. Most come from its opponents trying to make sense of it on their own terms. In trying to formulate it in a way that makes sense given their anti-CR premises, they change it. It's best to read primary sources for this.