As a narrative that claims to be an account of real events, it is crucial for Oroonoko that Behn—both author and narrator—use specific language to establish her credibility with the reader. She does so at the beginning of the novella, before relating any details of the story:
I was myself an eye-witness, to a great part, of what you will find here set down; and what I could not be witness of, I received from the mouth of the chief actor in this history, the hero himself, who gave us the whole transactions of his youth.
The narrator here establishes her credibility, thereby allowing her to use ethos, or the rhetorical appeal to authority, by claiming that she was either eyewitness to most of the events that take place over the course of Oroonoko, or received her information firsthand from the source. It was very common during this time period to see novels, novellas, and short stories written by citizens of colonizing empires, detailing the so-called "true stories" of their experiences abroad. Given that many of the people living in England, or France, or the Netherlands would never travel abroad to the places their governments had colonized, many of these fictitious stories were taken as true accounts. Behn's claim to be an "eye-witness" gives her readers permission to view Oroonoko in the same way.