判断・推量N2
〜まい、〜まいか
probably won't... / never... / will not...
Structure
V-辞書形 + まい；V-ない形 + まい
Explanation
① negative speculation (probably won't...); ② the speaker's negative intention (never...). Godan verbs take the dictionary form; ichidan/suru verbs take the dictionary or nai-form.
Examples
彼はそんな約束を忘れるまい。
He won't forget a promise like that.
今度こそ、失敗するまいと心に決めた。
I resolved never to fail again this time.
Note
まいか is a rhetorical question (isn't it...?). The pattern is fairly literary.
Related Grammar
〜（の）ではあるまいか〜ないだろう