Unmistakable
Indisputable, Obvious
い adjective
紛らわしい is "confusing" or "misleading." This is the negative of that (you can tell by the ない), meaning it's kind of the opposite of those things. This word is unmistakable, indisputable , and obvious.
The reading comes from 紛らわしい.
彼女は紛れもない田舎っぺの女の子だ。
She is an unmistakable country bumpkin girl.