〜とは限らない
Not necessarily 〜とは限らない
Meaning
"Not necessarily ~", "it is not always the case that ~".
Formation
[plain form] + とは限らない · [noun] + とは限らない
Notes
Denies that something holds in every case, without denying it outright. Often introduced by 必ずしも: 高いものが必ずしもいいとは限らない. Compare わけではない, which denies a specific inference rather than a general rule.
Examples
高（たか）いものがいいとは限（かぎ）りません。
Expensive things are not necessarily good.
Breakdown
日本人（にほんじん）がみんな寿司（すし）が好（す）きだとは限（かぎ）らない。
Not all Japanese people necessarily like sushi.
Breakdown
努力（どりょく）すれば必（かなら）ず成功（せいこう）するとは限（かぎ）りません。
Working hard does not always mean you will succeed.
Breakdown
天気予報（てんきよほう）が当（あ）たるとは限（かぎ）らない。
The forecast is not always right.
Breakdown
有名（ゆうめい）な店（みせ）がおいしいとは限（かぎ）りません。
A famous restaurant is not necessarily a good one.
Breakdown
⚠️ Often confused with
〜わけだ
That is why 〜わけだ
Draws a conclusion that follows naturally — "so that's why ~", "no wonder ~", "it works ou...
〜わけではない
It is not that 〜わけではない
A partial denial — "it is not that ~", "that does not mean ~". Softens rather than rejects...
〜わけがない
There is no way 〜わけがない
A flat denial of possibility — "there is no way ~", "it is impossible that ~".
〜に決まっている
Bound to be 〜に決まっている
Says an outcome is obvious — "of course ~", "it is bound to be ~".
〜ものだ
One should / used to 〜ものだ
Three uses: a general truth, nostalgia for what one used to do, and mild moral advice.
〜っこない
Could not possibly 〜っこない
A blunt, casual denial — "there is no chance ~", "could not possibly ~".
〜に過ぎない
Merely 〜に過ぎない
"Merely ~", "no more than ~".
〜というものだ
That is what ~ is 〜というものだ
"That is what ~ really is" — the speaker's verdict stated as a general truth.
〜にほかならない
Nothing other than 〜にほかならない
"Is nothing other than ~", "is precisely ~".