But he sure is fast vs Definitely vs Really

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

But he sure is fast

Top 3,000 (common)

Definitely

Top 1,000 (very common)A2adverb

Really

Top 1,000 (very common)A1adverb
 But he sure is fastDefinitelyReally
Pronunciation🇬🇧 //bʌt hiː ʃʊə ɪz fæst//🇺🇸 //bʌt hiː ʃʊr ɪz fæst//🇬🇧 /["/ˈdefɪnətli/"]/🇺🇸 /["/ˈdefɪnətli/"]/🇬🇧 /["/ˈriːəli//ˈrɪəli/"]/🇺🇸 /["/ˈriːəli/"]/
MeaningHe is definitely quick.For sure, without a doubtvery or truly
ExampleBut he sure is fast when it comes to running.I definitely remember sending the letter.I really enjoy going to the beach.
RegisterNeutralNeutralNeutral
How commonTop 3,000 (common)Top 1,000 (very common)Top 1,000 (very common)
CEFR level-A2A1
Part of speechadverbadverb
Collocationshe sure is, but he, is fastdefinitely agree, definitely believe, definitely knowreally want, really good, really sure, really excited, really important
Antonyms-doubtfully, uncertainlyseldom, never
Common mistakesUsing 'sure' without 'but' in a contrasting statement., Confusing 'fast' with 'quick' - they are similar but have different usages in context.Often confused with 'defiantly' which means resisting authority., Sometimes spelled incorrectly as 'definately'.Using it in place of 'real' when describing a noun., Confusing it with 'really' in terms of degree, e.g., 'really good' instead of 'very good'.
Usage notesUse in informal contexts, such as conversations or storytelling. Avoid in formal writing.Use 'definitely' to emphasize certainty. It fits well in both spoken and written English. Avoid using it in overly formal contexts where alternatives like 'certainly' might be more suitable.Used to emphasize an adjective or another adverb. It can be informal in casual conversations but is accepted in most contexts; avoid overusing it in formal writing.

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But he sure is fast
Definitely
Really

Frequently asked questions: But he sure is fast vs Definitely vs Really

What's the difference between But he sure is fast, Definitely, and Really?

But he sure is fast: He is definitely quick. Definitely: For sure, without a doubt Really: very or truly

Which is more advanced: But he sure is fast, Definitely, and Really?

Definitely is the highest level, at A2, on the CEFR scale.

Can you show an example of each?

But he sure is fast: But he sure is fast when it comes to running. Definitely: I definitely remember sending the letter. Really: I really enjoy going to the beach.

Can I use But he sure is fast, Definitely, and Really interchangeably?

Not always. But he sure is fast, Definitely, and Really 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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