How to Say "Not True" in Japanese

本当ではない

hontō dewa nai

The English phrase "not true" is expressed in Japanese as 本当ではない (hontō dewa nai).

This phrase is used to state that a piece of information is incorrect or false.

What does it mean word for word?

The word 本当 (hontō) literally means "truth" or "reality".

The polite version of 本当ではない is 本当ではありません. In casual speech, the dewa nai part is often shortened to じゃない, resulting in 本当じゃない.

hontō dewa nai

The word hontō is written with characters meaning 'true' and 'road'. This suggests a conceptual link between truth and a straight path.
In high-context social situations, a Japanese speaker might avoid saying 本当ではない entirely and instead use a long silence or a vague そうですね (sō desu ne) to imply that a statement is not true.
When expressing that something is 'not true' in a formal or business setting, Japanese people often use the phrase chigaimasu, which literally means 'it differs'.

噂は僕の知る限り本当ではない。
The rumor is not true as far as I know.
This sentence shows how to use 本当ではない to say a rumor is not true based on one's knowledge.
Tatoeba #189486 by small_snow, translation #26637 by CK
私の知る限り、うわさは本当ではない。
As far as I know, the rumor is not true.
This sentence is another way to express that a rumor is not true using 本当ではない.
Tatoeba #163059 by bunbuku, translation #251454 by CK
あなたの言ったことは本当ではない。
What you said is not true.
This sentence uses 本当ではない to state that someone's words are not true.
Tatoeba #1357765 by marcelostockle, translation #70697 by CK
それは真実ではありません。
That is not true.
彼の話は違います。
His story is not true.
本当じゃないよ！
It's not true!
彼の言っていることは違うよ。
What he is saying is not true.
本当ですか？
Is that true?
2 more sentences on Tatoeba

Yota and Himari are talking about a rumor at school.

陽葵 Himari

陽太が転校するって本当？
Yōta ga tenkō suru tte hontō?
Is it true that you are transferring schools, Yota?
陽太 Yota

そんな話は本当ではないよ。
Sonna hanashi wa hontō de wa nai yo.
That story is not true.
陽葵 Himari

よかった。びっくりしたよ。
Yokatta. Bikkuri shita yo.
What a relief. You surprised me.
陽太 Yota

誰がそんなことを言ったのかな。
Dare ga sonna koto o itta no kana.
I wonder who said such a thing.

Sources

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