ためにする

expression, suru verb (irregular)

have an ulterior motive; have an axe to grind

Used when someone's actions are not straightforward but driven by a hidden personal agenda. Often used in negative or suspicious contexts.

• 彼かれの親しん切せつはためにしているとしか思おもえない。

  I can't help thinking his kindness has an ulterior motive.

• あの政せい治じ家かの発はつ言げんは、ためにしているに違ちがいない。

  That politician's remarks must have an axe to grind.