speak the truth 是一个固定搭配
说实话
例句:
I adjure you to speak the truth.
你务必对我说实话.
He wants the courage to speak the truth.
他缺乏说实话的勇气.
speak 后面还可以跟语言 speak English speak Chinese
说实话还可以用其他词 tell the truth 也行