Translation guide
In Japanese, a 'verbal promise' is commonly expressed with words meaning 'oral promise' or 'verbal agreement.' The most natural term is 口約束 (kuchiyakusoku), but other options exist depending on formality and context.
A promise made by speaking, not written down.
The most direct and common translation for 'verbal promise.' It literally means 'mouth promise' and is used in everyday conversation.
I'm uneasy with just a verbal promise.
He didn't keep his verbal promise.
A slightly more formal phrase meaning 'oral promise.' 口頭 (kōtō) means 'oral' or 'verbal' in formal contexts.
An oral promise is also legally valid.
A more literary or formal term for 'verbal promise.' Rarely used in daily speech.
To exchange verbal promises.
An agreement made through spoken words, often in business or legal contexts.
口約束 (kuchiyakusoku) is the everyday term for a casual verbal promise. 口頭での約束 (kōtō de no yakusoku) is more formal and often used in legal or business contexts. For most situations, 口約束 is sufficient.
I forgot the verbal promise I made with my friend.
An oral promise leaves no evidence.
Do not translate 'verbal promise' as 言葉の約束 (kotoba no yakusoku) or 言語約束 (gengo yakusoku). These are unnatural and not used in Japanese.
An oral agreement should be put in writing.