Promise vs Swear to God

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

Promise

Top 1,000 (very common) A2 verb

Swear to God

Informal Top 3,000 (common)

Most formal: Promise Most common: Promise

	Promise	Swear to God
Pronunciation	🇬🇧 /["/ˈprɒmɪs/","/ˈprɒmɪsɪz/","/ˈprɒmɪst/","/ˈprɒmɪsɪŋ/"]/ 🇺🇸 /["/ˈprɑːmɪs/","/ˈprɑːmɪsɪz/","/ˈprɑːmɪst/","/ˈprɑːmɪsɪŋ/"]/	🇬🇧 //swɛə tʊ ɡɒd// 🇺🇸 //swɛr tə ɡɑd//
Meaning	A commitment to do something or not do something.	To promise seriously, often while making a strong statement.
Example	I promise to help you with your homework.	I swear to God, I didn’t take your book!
Register	Neutral	Informal
How common	Top 1,000 (very common)	Top 3,000 (common)
CEFR level	A2	-
Part of speech	verb
Collocations	faithfully, solemnly, initially, can, cannot, seem to, to, as promised, I can’t promise anything	swear to God that, I swear to God, swear to God in court
Antonyms	lie, break, betray	-
Common mistakes	Confusing 'promise' with 'vow' or 'pledge' in terms of strength., Using 'promise' without an object (e.g., 'I promise' should specify what)., Misusing in the past tense (e.g., 'I promised' without a follow-up).	Using it in a formal context., Confusing it with 'swear on the Bible' which has a religious connotation.
Usage notes	Use 'promise' when you want to express a vow or assurance. Common in both spoken and written contexts, but avoid in formal legal documents.	Used in informal contexts to emphasize honesty or seriousness. Not suitable for formal writing or discussions.

See it in real clips

And one system shows promise.

and I always try to keep my promise.

And one system shows promise.

and I always try to keep my promise.

Promise

House Of Cards › S1 E1

It was just this one time, Frank. I swear to God.

Swear to God

Frequently asked questions: Promise vs Swear to God

What's the difference between Promise and Swear to God?

Promise: A commitment to do something or not do something. Swear to God: To promise seriously, often while making a strong statement.

Which is more formal: Promise and Swear to God?

Promise is the most formal of these.

Which is more common: Promise and Swear to God?

Promise is the most common in everyday English.

Can you show an example of each?

Promise: I promise to help you with your homework. Swear to God: I swear to God, I didn’t take your book!

Can I use Promise and Swear to God interchangeably?

Not always. Promise and Swear to God 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.