elementary, principle, naked, uncovered

どうやら、さっきのは演技ではなく、素だったらしい。

It seems like that she wasn't acting back then; they were her real feelings.

生粋のお嬢様だからな。残念ながら悪戯とかじゃなくてあれで素だ。

She's pure bred blue-blood you see. Unfortunately that's no sort of put-on but her natural self.

そ、そうじゃなくて、・・・ 素の自分、本当の私を必要としてくれる人がいるなんて、考えたこともありませんでしたから。

N-no it's not that ... it's that there could be someone who would need me for what I am, for my true self, I hadn't even thought of that possibility.