Nihongo no oshaberi 「Japanese Language Tidbit」

Verb Usage:
Verb Conjugation: Dictionary Form
「Vdic + Ni Chigainai にちがいない」
”Must be” "There is no doubt that~"

Vdic ni chigainai is used to express the speakers' guess with confidence
chigaiarimasen is used when using polite speech.

Examples:

Kodomo-tachi wa yorokobu ni chigainai.
子供達は喜ぶにちがいない。
There is no doubt that the children will be happy.

Nihongo no gakusei ga fueru ni chigaiarimasen.
日本語の学生が増えるにちがいありません。
The (number of) students of Japanese will undoubtedly increase.

Gijutsu wa shinpo suru ni chigaiarimasen.
技術は進歩するにちがいありません。
There is no doubt that technology will make progress.