んじゃない => can not, impossible to... N4
Ban
んじゃ => If ... then... N4
Condition (hypothetical condition)
んじゃないか => right? isn't it? let's~; confirmation N4
Confirm
んじゃない => confirmation of information; express surprise towards listener N4
Speculation
んじゃなかったか => shouldn't have... N4
Regret
じゃないが => It's not that... but... N4
How to say the beginning
じゃありません => not to be N5
Emphasize negative meaning
じゃないか => right? isn't it? let's~; confirmation N4
Speculation
んじゃないだろうか => could it be that ~; might it be that ~ N4
Speculation
じゃないか / ではないか => right? isn't it? N3
Confirm
じゃないか / ではないか => right?; isn't it? (Criticism) N3
Criticize
にほかならない/からにほかならない => nothing but; none other than ~ N2