Sentence:  Ye are next to aſſure all Perſons, who are ſo kind as to give you Audience, that to prevent the leaſt Suſpicion of <WSD>Spurioſity</WSD>, they may ſee every Letter I have ever printed of Mr. "Pope'''s in his "Own Hand-Writing", ... 
Meaning of the word marked with <WSD> tags:  Spuriousness.