Grammar › Speculation & Certainty
ないとも限らない — “can't say for certain that… won't, might well”
Leaves open the possibility of an unlikely but not impossible outcome
Plain negative (or plain form) + とも限らない says that, while something may seem unlikely, it can't be completely ruled out — “you can't say it definitely won't happen.” The double negative layers here (ない + とも限らない) to leave room for a small but real possibility.
How to form it
| Pattern | Example |
|---|---|
| Plain form + とも限らない | 失敗しないとも限らない — It's not like failure is impossible |
Example sentences
| Japanese | Reading | Meaning |
|---|---|---|
| このままでは事故が起きないとも限らない。 | このままではじこがおきないともかぎらない。 konomamadehajikogaokinaitomokagiranai。 | At this rate, we can't rule out an accident happening. |
| 彼が本当のことを言っているとも限らない。 | かれがほんとうのことをいっているともかぎらない。 karegahontounokotowoitteirutomokagiranai。 | We can't be sure he's telling the truth, either. |
| 明日晴れるとも限らないので、傘を持って行こう。 | あしたはれるともかぎらないので、かさをもっていこう。 ashitaharerutomokagiranainode、kasawomotteikou。 | There's no guarantee it'll be sunny tomorrow, so let's bring an umbrella. |
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Watch out
とも限らない is a soft hedge that leaves a small possibility open — it isn't a strong warning like 恐れがある; it just resists ruling something out entirely.