Translation guide
A hidden reason for doing something, often selfish or dishonest. In Japanese, this is commonly expressed with set phrases like 下心 or 魂胆, or by describing the hidden intention with words like 隠された意図.
To express that someone has a secret, usually self-serving, reason behind their actions.
The most common and direct equivalent. Implies a secret, often selfish or calculating intention behind a friendly or helpful act.
To describe a concealed reason or agenda without the negative connotation of selfishness.
Direct translations like 隠された動機 are understandable but sound unnatural. Use established terms like 下心 or 魂胆 for natural Japanese.
下心 is often used with verbs like ある (to have), 見え見え (obvious), or 感じる (to sense).
I think he has an ulterior motive for being so kind.
There's an ulterior motive hidden behind that smile.
A slightly more calculating or scheming nuance than 下心. Often used when someone has a hidden plan or scheme.
He must have some ulterior motive for suddenly becoming so nice.
A more literal and neutral way to say 'hidden intention'. Can be used in formal or analytical contexts.
It seems like there's an ulterior motive behind that proposal.
Literally 'other intention'. Often used in negative form 他意はない to deny having an ulterior motive. Somewhat formal.
I have no ulterior motive. I just wanted to help.
There's an ulterior motive behind his actions.
Means 'true aim'. Used when the real objective is different from the apparent one.
No one knows what his ulterior motive really is.