でたらめじゃありません
出鱈目じゃありません
detaramejārimasen

Noun
Desu Copula
na-Adjective
Negation Auxiliary

The polite negative form of でたらめ

1. It is not nonsense.; It is not a lie.; It is not made up.

Negative
Polite
Terminal Form
Usually Written in Kana