Assure or ensure?
assure is a verb meaning “To make sure and secure; ensure”; ensure is a verb meaning “To make sure or certain of something (usually some future event or condition)”. In written English (wordfreq, 2021 data) ensure is about 4.4 times as common as assure.
What is the difference between assure and ensure?
| assure | ensure | |
|---|---|---|
| Part of speech | verb | verb |
| Meaning | To make sure and secure; ensure To give (someone) confidence in the trustworthiness of (something) | To make sure or certain of something (usually some future event or condition) |
| Example | I assure you that the program will work smoothly when we demonstrate it to the client | I use an alarm clock to ensure that I get up on time |
| Forms | assures, assuring, assured | ensures, ensuring, ensured |
| Pronunciation | /əˈʃɔː(ɹ)/ /əˈʃʊə(ɹ)/ /əˈʃʊɹ/ | /ɪnˈʃɔː(ɹ)/ /ɪnˈʃʊə(ɹ)/ /ɪnˈʃʊɹ/ |
| In writing | 11 times per million words | 50 times per million words |
Sources: assure and ensure in the English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0); written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
Every current meaning of assure and ensure
assure
- 1
To make sure and secure; ensure
- 2
To give (someone) confidence in the trustworthiness of (something)
I assure you that the program will work smoothly when we demonstrate it to the client
- 3
To reassure
ensure
- 1
To make sure or certain of something (usually some future event or condition)
I use an alarm clock to ensure that I get up on time
Source: the English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0); obsolete, archaic, dialect and rare senses left out.
Which is more common, assure or ensure?
assure appears 11 times per million words; ensure 50 times per million words.
assure 11 times per million wordsensure 50 times per million words
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How many people search assure vs ensure?
“assure vs ensure” is searched about 6,600 times a month on Google and 790 on Bing in the United States. Google counts close variants of a query together (“ensure vs assure”, “assure or ensure”).
Sources: Google Ads keyword data through DataForSEO and Microsoft Advertising keyword data through DataForSEO, the average month from September 2025 to August 2026.