ではないか

(De ha nai ka)

Used to express surprise, discovery, or to strongly assert an opinion.

Connection rules

素晴すばらしいアイデアではないか。

Subarashii aidea de ha nai ka.

Isn't that a wonderful idea?

「Manager praising a plan」

君きみも一緒いっしょに行いくと言いったではないか。

Kimi mo issho ni iku to i ta de ha nai ka.

You did say you were going together, didn't you?

「Reminding a friend」