from https://www.evenmere.org/~bts/Random-Collected-Documents/princess_bride.html
Westley: Well, one thing I will say; the fire swamp certainly does keep you on your toes. This will all soon be but a happy memory. [Westley cuts through a mass of vines] Robert's ship Revenge is banked at the far end. And as you know I am Roberts. Buttercup: But how's that possible, since he's been marauding 20 years and you only left me 5 years ago? Westley: I myself am often surprised at life's little quirks. See, what I told you before about saying please was true...it intrigued Roberts, as did my descriptions of your beauty. Finally, Roberts decided something. He said, 'Alright Westley, never had a valet, you can try if you'd like. I'll most likely to kill you in the morning.' For three years said that. 'Good night Westley, good work, sleep well, I'll most likely to kill you in the morning.' It was a fine time for me - I was learning to fence, fight, anything anyone would teach me. Roberts and I eventually became friends. And then it happened. Buttercup: What? Go on. Westley: Well Roberts had grown so rich, he wanted to retire. He took me to his cabin and told me his secret. 'I am not the Dread Pirate Roberts,' he said 'my name is Ryar. I inherited this ship from the previous Dread Pirate Roberts, just as you will inherit it from me. Westley: [continuing] The man I inherited it from was not the real Dread Pirate Roberts either - his name was Cumberbun. The real Roberts had been retired 15 years and was living like a king in Patagonia.' Thank you. Then he explained the name was the important for inspiring the necessary fear. You see, no one would surrender to the Dread Pirate Westley. So we sailed ashore, took on an entirely new crew and he stayed aboard for awhile as first mate, all the time calling me Roberts. Once the crew believed, he left the ship and I have been Roberts ever since. Except now that were together, I shall retire and hand the name over to someone else. Is everything clear to you?