matter of fact   (TTS發音)

sth. that is really true； sth. that can be proved事實

    It's a matter of fact that he runs faster than you do. 他比你跑得快，這是事實。

    Mary wasn't wearing a blue dress. As a matter of fact，she hasn't got a blue dress. 瑪麗沒有穿藍衣服，事實上她根本就沒有藍衣服。