(1) truth指“真理，真相，真实性”。

• Do you acknowledge the truth of his account of the event?
  你认可他对事件陈述的真实性吗？
• We must feel out/clear up/clarify the truth of the secrecy.
  我们必须弄清这个秘密的真相。
• He thought the report distorted truth and facts/stood truth on its head/withheld the truth from the public.
  他认为这则报道歪曲了事实真相/颠倒是非/对公众隐瞒了真相。
• We hold these truths to be self-evident.
  我们认为这些真理是不言自明的。
• We should always seek after/uphold/follow the truth .
  我们应该永远追求/坚持/追随真理。
• To tell the truth , I don't think well of his performance.
  说实话，我认为他表演得不好。

 (2) in (all) truth指“说老实话”，较正式。

• In all truth , I must admit I don't like him very much.
  说老实话，我必须承认自己不太喜欢他。

 (3) truthfulness指“诚实，真实”。

• I like him for his truthfulness .
  我喜欢他的诚实。
• Nobody can prove the truthfulness of his history.
  没人能证明他的经历的真实性。

 (4) reality指“现实(情况)，真实性，真实存在”。

• We must have the courage to face up to reality rather than to escape from it.
  我们必须勇于面对现实而不是逃避。
• She believed in the reality of fairies.
  她相信仙子真的存在。
• His dream of going abroad to further his studies became a reality .
  他去国外深造的梦想终成现实。

 (5) in reality意思是“事实上，实际上”，常用来纠正另一情况。

• I thought he was serious but in reality he was joking.
  我以为他是认真的，而事实上他在开玩笑。
• The image you see in mirage is not there in reality . It is merely an illusion.
  你在海市蜃楼中看到的景象不是真实存在的，那只不过是种幻觉。

 (6) fact指“事实”。

• He is quite aware of the fact that the manager doesn't think much of his work.
  他很清楚这样一个事实：经理对他的工作评价不高。
• The fact is, he didn't come at all.
  事实是，他根本就没来。
• I think his remarks lack fact/facts .
  我认为他的话没有事实依据。
• We should have the courage to face facts .
  我们应有面对事实的勇气。

 (7) as a matter of fact, in (actual) fact, in point of fact这些短语均表示“事实上，实际上，说实在的”，在句中常用作插入语。

• Officially he is in charge of the school, but in actual fact his wife does all the work.
  对外是他管理这个学校，而实际上是他的妻子打理所有的事务。
• He doesn't mind at all, and, in point of fact , he is very pleased.
  他根本不介意，而实际上，他是非常高兴的。
• He did come to the meeting, as a matter of fact .
  事实上，他确实是来开会了。

 (8) actuality意为“现实性”。

• More often than not, you have to accept the actualities of life.
  多数情况下，人必须要接受生活的现实。

 (9) in actuality意为“事实上，实际上”，常用于纠正某个情况。

• He looks poor but in actuality he has money to burn!
  他看起来很穷，实际上他很有钱。