心直口快　

◎ 心直口快 xīnzhí-kǒukuài

[frank and outspoken;carry one‘s heart upon one‘s sleeves;say what one thinks without much deliberation] 性情直爽,有话就说

薛蟠本是个心直口快的人,见不得这样藏头露尾的事。——《红楼梦》