This is the 2336th most frequent Japanese word.
なんとも
"なんとも" means "quite," "really," "nothing (negative contexts)," or "beyond description," depending on context.
Here, 'なんとも' is used as an expression of admiration or amazement, effectively conveying 'how' or 'what.'
なんともきれいな景色だ。
What a beautiful scenery!
In this sentence, 'なんとも' functions to emphasize the mysterious nature of the subject, conveying 'truly' or 'indeed.'
彼の話はなんとも不可思議だ。
His story is truly mysterious.
Here, 'なんとも' is used to express an inability to aptly describe a situation or feeling, meaning 'cannot be adequately expressed.'