know for certain

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

If we don’t know for certain whether brain training can lower the risk of dementia, but it might just, then why wouldn’t we do it?

From MarketWatch • Feb. 11, 2026

Given the lack of any count over time, it’s impossible to know for certain how agents’ current use of the banned and dangerous tactics compares with earlier periods.

From Salon • Jan. 14, 2026

Forecasting snow in the UK is notoriously difficult, and it is still too early to know for certain whether we will see a white Christmas in 2025.

From BBC • Dec. 12, 2025

We can’t know for certain if the Values Bridge data reveals a slow trend away from the centrality of family in the American psyche or a sudden drop, or why in either case.

From The Wall Street Journal • Nov. 20, 2025

All they know for certain is that, as soon as Mr. Wigg had appealed to Mary Poppins, the table below began to wriggle on its legs.

From "Mary Poppins" by P. L. Travers