Truth is the opposite of falsehood and that is all. You tell a lie, withhold the truth, or you tell the truth. And the stinging consequence of lying and telling the truth escalates.
The truth matters to the people who appreciate it. And the consequence stings because the truth cannot be handled. Some people feel just as bad telling the truth than they do telling a lie. It all depends on feelings and their conscious.
To convince something is the truth is like convincing someone that their brothers and sisters aren’t related to them at all. People will believe what they want to believe according to the impression they have on the person. Maybe their respect for the teller may change their mind. Maybe it depends on their physical conviction. But in any situation concerning telling the truth or not, it all depends on whether or not the teller feels like lying.