Translation of "Undoubtedly" in Japanese

That's an unusual thing, undoubtedly.

それは全く異例のことだ。

Haruyo is undoubtedly under stress during this entrance-examination season.

ハルヨは入試の季節になると、必ず緊張をする。

- He must have made it up.
- Undoubtedly, he made it up.

彼はそれをでっち上げたに違いない。

The English language is undoubtedly the easiest and at the same time the most efficient means of international communication.

英語は明らかに、最も簡単であると同時に最も効率の良い国際コミュニケーションの手段です。

- She must've been beautiful when she was young.
- She certainly was a beautiful woman when she was young.
- She was undoubtedly a beautiful woman when she was young.

- 彼女は若い頃美しかったに違いない。
- 彼女は若い頃は美人だったに違いない。
- 彼女は若いころ美人だったに違いない。

Tom was undoubtedly the most intelligent student in the entire school, but whenever the teacher asked him a question for which he was not prepared, he was filled with such nervousness that he would become confused, and something utterly incomprehensible would issue from his mouth as soon as he opened it.

トムは疑いなく学校中で一番頭のいい生徒だったが、先生に不意に当てられるといつもすっかりあがってしまい、口を開くや否や全く訳の分からないことをしどろもどろに口走るのだった。