N2
まい
Won't, Intend not to, Probably not
あんな接客が雑なレストランにはもう行くまい。
I won't go back to that restaurant with such sloppy service.
Explanation
「まい」 has 2 uses
1Resolve not to
The speaker resolves never to do it: 「二度とあんな店へは行くまい」 (I'll never go to that shop again).
あの店は行列がすごすぎる。もう行くまい。
The line at that shop is too crazy. I won't go there again.
あんな接客が雑なレストランにはもう行くまい。
I won't go back to that restaurant with such sloppy service.
2Probably not
A guess that something probably won't happen: 「彼もそこまでは言うまい」 (he probably wouldn't go that far). Common as 「〜ではあるまい」「〜ことはあるまい」.
今日は火曜日だから、あのダンスクラブにはお客さんはいるまい。
Because it is Tuesday, there probably won't be many people at that dance club.
この車の見た目からすると安くはあるまい。
Judging from the appearance of this car, it is probably not cheap.