Cool MateCertainly vs You know her of course
When to use each in English, with meaning, register, and examples.
Certainly
Top 1,000 (very common)A2adverb
You know her of course
Top 5,000 (fairly common)
Most common: Certainly
| Certainly | You know her of course | |
|---|---|---|
| Pronunciation | 🇬🇧 /["/ˈsɜːtnli/"]/🇺🇸 /["/ˈsɜːrtnli/"]/ | 🇬🇧 //juː nəʊ hɜːr əv kɔːs//🇺🇸 //juː noʊ hɜr əv kɔrs// |
| Meaning | Definitely; for sure. | You are familiar with her, obviously. |
| Example | Without treatment, she will **almost certainly** die. | You know her, of course, she’s your sister! |
| Register | Neutral | Neutral |
| How common | Top 1,000 (very common) | Top 5,000 (fairly common) |
| CEFR level | A2 | - |
| Part of speech | adverb | |
| Collocations | certainly agree, certainly possible, certainly not, certainly true, certainly yes | know her well, know him, of course, you know them too |
| Antonyms | uncertainly, doubtfully | - |
| Common mistakes | 'Certainly' is often incorrectly used in place of 'certain' in adjectives., Learners might confuse 'certainly' with 'definitely' without noticing the subtle nuance., Some learners use 'certainly' in inappropriate contexts, such as casual greetings. | Forgetting to use 'of course' for emphasis., Using 'you know her' without 'of course' can sound less confident., Confusing with similar phrases like 'you've met her'. |
| Usage notes | Use 'certainly' when you want to emphasize affirmation or agreement. It is more formal than 'sure' and works well in professional settings, but might feel too strong in casual conversations. | Used when confirming someone's familiarity with a person. Can be friendly or casual; avoid in formal writing. |
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Frequently asked questions: Certainly vs You know her of course
What's the difference between Certainly and You know her of course?
Certainly: Definitely; for sure. You know her of course: You are familiar with her, obviously.
Which is more common: Certainly and You know her of course?
Certainly is the most common in everyday English.
Can you show an example of each?
Certainly: Without treatment, she will **almost certainly** die. You know her of course: You know her, of course, she’s your sister!
Can I use Certainly and You know her of course interchangeably?
Not always. Certainly and You know her of course are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.