But he sure is fast vs Certainly

When to use each in English, with meaning, register, and examples.

But he sure is fast

Top 3,000 (common)

Certainly

Top 1,000 (very common)A2adverb
Most common: Certainly
 But he sure is fastCertainly
Pronunciation🇬🇧 //bʌt hiː ʃʊə ɪz fæst//🇺🇸 //bʌt hiː ʃʊr ɪz fæst//🇬🇧 /["/ˈsɜːtnli/"]/🇺🇸 /["/ˈsɜːrtnli/"]/
MeaningHe is definitely quick.Definitely; for sure.
ExampleBut he sure is fast when it comes to running.Without treatment, she will **almost certainly** die.
RegisterNeutralNeutral
How commonTop 3,000 (common)Top 1,000 (very common)
CEFR level-A2
Part of speechadverb
Collocationshe sure is, but he, is fastcertainly agree, certainly possible, certainly not, certainly true, certainly yes
Antonyms-uncertainly, doubtfully
Common mistakesUsing 'sure' without 'but' in a contrasting statement., Confusing 'fast' with 'quick' - they are similar but have different usages in context.'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.
Usage notesUse in informal contexts, such as conversations or storytelling. Avoid in formal writing.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.

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But he sure is fast
Certainly

Frequently asked questions: But he sure is fast vs Certainly

What's the difference between But he sure is fast and Certainly?

But he sure is fast: He is definitely quick. Certainly: Definitely; for sure.

Which is more common: But he sure is fast and Certainly?

Certainly is the most common in everyday English.

Can you show an example of each?

But he sure is fast: But he sure is fast when it comes to running. Certainly: Without treatment, she will **almost certainly** die.

Can I use But he sure is fast and Certainly interchangeably?

Not always. But he sure is fast and Certainly 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.

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