ではありますまいか

expression

I wonder if it is not; isn't it perhaps

A formal, somewhat old-fashioned rhetorical expression used to politely suggest that something is likely the case. Often used in writing or formal speech to soften an assertion.

• この計けい画かくには問もん題だいがあるのではありますまいか。

  I wonder if there isn't a problem with this plan.

• 彼かれの説せつ明めいは少すこし不ふ十じゅう分ぶんなのではありますまいか。

  Isn't his explanation perhaps a little insufficient?