Definition
a concealed or secret motivation behind an action or statement.
別有用心
Her compliments sounded genuine, but I suspected she had an ulterior motive.
她的稱讚聽起來很真誠，但我懷疑她別有用心。
He made a generous donation to charity, but people thought he had an ulterior motive to improve his image.
他向慈善機構慷慨捐款，但人們認為他別有用心想改善形象。
She appeared to be helping, but in reality, she had an ulterior motive to profit from it.
她看似在幫忙，但實際上別有用心想從中獲利。