I don't think it is true that faith necessarily implies uncertainty. As I understand it, faith is a kind of spiritual perception granted by God. It is a different certainty than that which we obtain by experiencing things through our senses, but not, as far as I know, a belief in the face of inherent doubt.

I think it's also worth pointing out that cults defend their claims of certainty by attacking dissidents. An institution with legitimate truth claims would allow people to freely come to an understanding of that truth, which is indeed what the Church does.