Don't believe it. Don't believe it at all. DeVere's known writing is nothing like Shakespeare's. Shakespeare had a facility with meter unmatched by an other poetry. That's why poets like Worsdworth can tell which lines were written by Shakespeare, and which were filled in by others.
Believe it. Edward de Vere, the 17th Earl of Oxford, wrote the works attributed to William Shakespeare. They don’t even know if the glove maker’s son could read and write.