～とは限らない — Not Necessarily So
Used to say that something is 'not necessarily' or 'not always' true. It denies a general assumption or common belief, pointing out that exceptions exist. It softens absolute statements by leaving room for cases where the expected outcome does not apply.
Structure
[Plain form (verb / い-adj / noun+だ / な-adj+だ)] + とは限らない
Examples
高いものがいいとは限らない。
Takai mono ga ii to wa kagiranai.
Expensive things are not necessarily good.
いい (good, plain) + とは限らない denies the assumption that price equals quality
日本人だからといって、寿司が好きだとは限らない。
Nihonjin da kara to itte, sushi ga suki da to wa kagiranai.
Just because someone is Japanese doesn't mean they necessarily like sushi.
な-adj 好きだ + とは限らない rejects the stereotype
努力すれば必ず成功するとは限らない。
Doryoku sureba kanarazu seikou suru to wa kagiranai.
Making an effort doesn't necessarily mean you will succeed.
Verb 成功する + とは限らない; often paired with 必ず (always) to stress the exception
• Often appears with adverbs like 必ずしも or いつも to reinforce the 'not always' meaning. • Register: neutral; common in essays and discussion. • It denies a general rule, not a specific single fact.
Commonly confused with
The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones ～とは限らない is tested against.
vs わけではない
とは限らない denies that a general rule always holds ('not always'), while わけではない denies a specific conclusion drawn from context ('it's not that...').
More modal expressions
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