1. 实情;真相;事实
    The truth about something is all the facts about it, rather than things that are imagined or invented.

    e.g. Is it possible to separate truth from fiction?…
           有可能把事实与虚构分开吗？
    e.g. I must tell you the truth about this business...
           我必须告诉你这件事的真相。

2. 真实性;真实
    If you say that there is some truth in a statement or story, you mean that it is true, or at least partly true.

    e.g. There is no truth in this story...
           这个故事纯属虚构。
    e.g. Is there any truth to the rumors?...
           那些谣言有什么事实依据吗？

3. 真理
    A truth is something that is believed to be true.

    e.g. It is an almost universal truth that the more we are promoted in a job, the less we actually exercise the skills we initially used to perform it.
           这几乎是一条普遍的真理：我们在某一工作中越往上晋升，实际运用那些当初在工作中经常实践的技能的机会就越少。

4. see also: home truth;moment of truth

5. 实际上;事实上
    You say in truth in order to indicate that you are giving your honest opinion about something.

    e.g. In truth, we were both unhappy.
           事实上，我们俩都不快乐。

6. 说实在的;坦白说
    You say to tell you the truth or truth to tell in order to indicate that you are telling someone something in an open and honest way, without trying to hide anything.

    e.g. To tell you the truth, I was afraid to see him...
           坦白说，我害怕见他。
    e.g. Truth to tell, John did not want Veronica at his wedding.
           说实在的，约翰不想韦罗妮卡参加他的婚礼。