Questions & Answers about Non devi credere a una tale assurdità!
Why is there a una before tale? Could I just say a tale assurdità?
Yes, you can drop the article. When used as an adjective meaning "such", tale can be preceded by the indefinite article (una tale assurdità) or used on its own (tale assurdità). Both are perfectly correct, though using the article feels slightly more emphatic.
Why do we say credere a instead of just credere una tale assurdità?
In Italian, the verb credere (to believe) is generally intransitive when you are talking about believing a fact, a story, or a concept, so it requires the preposition a. You are literally saying you shouldn't give belief "to" such an absurdity.
Could una tale mean "a certain" in this sentence?