We do have ways of cross-checking things; indeed, the method that the real historians work with already takes this into account by its very nature. Of course, more can always be said, so if anyone would like to speak further on how historians deal with texts, please go ahead! You'll also be helping a complete bloody amateur at this.

For the meantime, as this question has arisen before, I commend to your attention the following posts:

• a now-deleted user explains how even deliberately falsified information can be useful;
• u/baliev23 examines how historians determine source validity;
• u/crrpit and u/PartyMoses have the most direct addressing of your concern, outlining how historians do business;
• and there's this Monday Methods post on reading primary sources critically, with multiple contributions from multiple people.