Used and loved by millions

Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.

Justyna Jupowicz-Kozak

CEO of Professional Science Editing for Scientists @ prosciediting.com

I'm definitely sure
Grammar usage guide and real-world examples

Table of contents

Usage summary

Human-verified examples

Expert writing tips

Linguistic context

Ludwig's wrap-up

Alternative expressions

FAQs

Human-verified examples from authoritative sources

Exact Expressions

6 human-written examples

I'm definitely sure I chose the right course".

News & Media

Independent

Marina, now in her early 50s, said, "All the same, I'm definitely sure he didn't do it, even if I'm still mad at him.

News & Media

The New Yorker

"I'm definitely sure I'm not sure about it," the brothers harmonized, sounding more like the boys fans would meet in school than dream lovers.

News & Media

The New York Times

"I'm definitely sure that the area itself is ready for a conflict, but you need external players also to fund and help and buy weapons and also the political decision for it," said Sahar Atrache, an analyst with the International Crisis Group.

News & Media

The New York Times

And I'm definitely sure that had an impact because we ultimately won the deal. .

News & Media

TechCrunch

I'm definitely sure I didn't see anyone in a tie.

News & Media

Vice

Human-verified similar examples from authoritative sources

Similar Expressions

54 human-written examples

When I passed people on the street who were laughing I was definitely sure they were laughing at me. $15 million cash.

News & Media

TechCrunch

"I am definitely sure that I'm going to fill out the paperwork and have [the drug], because to not have it would be like not taking advantage of something that's in your toolbox".

News & Media

Los Angeles Times

Another combative stockholder by the name of Souermundt also attended, he was definitely sure that it was "a packed meeting".

News & Media

The New Yorker

Now we're definitely sure because the schedule for dealing with closing up shops has been released.

News & Media

TechCrunch

Professor of clinical allergy research and panel member, Annika Scheynius, said: "We are definitely sure that these discoveries will lead to health improvement, mainly in the terms of new vaccines.

News & Media

BBC

Expert writing Tips

Best practice

In narrative writing, this phrase is excellent for character dialogue to reveal a strong-willed or persuasive personality.

Common error

Avoid using "I'm definitely sure" in academic or strictly formal business reports. Since "sure" is a binary state, adding "definitely" can be seen as wordy. Use "I am certain" or simply "I am sure" instead.

Antonio Rotolo, PhD

Digital Humanist | Computational Linguist | CEO @Ludwig.guru

Source & Trust

84%

Authority and reliability

4.8/5

Expert rating

Real-world application tested

Linguistic Context

The phrase "I'm definitely sure" consists of a first-person contraction, the copula verb "am", an adverbial intensifier "definitely", and a predicative adjective "sure". According to Ludwig, its primary function is to act as an emphatic declaration of confidence. The adverb modifies the adjective to remove any potential ambiguity about the speaker's stance.

Expression frequency: Uncommon

Frequent in

News & Media

65%

Wiki

20%

Social Media

10%

Less common in

Science

Formal & Business

Academia

Ludwig's WRAP-UP

In conclusion, "I'm definitely sure" is a robust and effective phrase for conveying absolute certainty in a variety of contexts. While it may be technically redundant, Ludwig examples demonstrate that its primary value lies in its rhetorical power and emotional weight. It is widely utilized in high-quality journalism and instructional guides to anchor a statement of fact or belief. When writing, remember that its strength comes from the intensifier, making it a perfect choice for personal narratives, interviews, and direct communication, even if more concise alternatives like ""I am certain"" might be preferred in scholarly papers.

More alternative expressions(10)

Phrases that express similar concepts, ordered by semantic similarity:

I'm absolutely sure

Uses a different intensifier that is often perceived as slightly more categorical

I'm quite certain

Replaces sure with certain and uses a more British-leaning intensifier

I'm entirely certain

Replaces definitely with entirely for a more encompassing tone

I'm positive

Uses a single adjective that inherently implies the high degree of certainty

I am convinced

Shifts the focus to the psychological state of being persuaded

I'm 100% sure

Uses a numerical metaphor to emphasize absolute confidence

I have no doubt

Uses a negative construction to define the absence of uncertainty

I'm definitely confident

Focuses on the speaker's internal feeling of self-assurance rather than the fact itself

It's beyond doubt

Removes the first-person perspective to make the claim sound more objective

I am sure

The base version of the phrase without the emphatic adverb

FAQs

Is it correct to say "I'm definitely sure"?

Yes, it is grammatically correct. While some stylists argue it is redundant because "sure" already implies certainty, it is a common way to add emphasis. You might also use "I'm absolutely sure" for a similar effect.

What is the difference between "I'm definitely sure" and "I'm pretty sure"?

"I'm definitely sure" conveys 100% confidence, whereas "I'm pretty sure" suggests a high but incomplete level of certainty, often around 80-90%.

Can I use "I'm definitely sure" in a business email?

It is acceptable in internal or casual business communication. For more formal external correspondence, consider using "I am confident that" or "I can confirm".

What can I say instead of "I'm definitely sure"?

Depending on the tone you want, you could use "I'm positive", "I'm certain", or "without a doubt".

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Table of contents

Usage summary

Human-verified examples

Expert writing tips

Linguistic context

Ludwig's wrap-up

Alternative expressions

FAQs

Source & Trust

84%

Authority and reliability

4.8/5

Expert rating

Real-world application tested

Most frequent sentences:

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I'm definitely sureGrammar usage guide and real-world examples

I'm definitely sure
Grammar usage guide and real-world examples