1.How can you show that you are truthful?

Truth Be Told:

Think before you speak.

Say what you mean and mean what you say.

Bend over backward to communicate in an open and honest fashion.

Simplify your statements so that everyone clearly understands your message.

Tell it like it is rather than sugarcoating it.

2.Give instances that one did an offense to truth.

Felonies and misdemeanors are two classifications of crimes used in most states, with petty offenses (infractions) being the third. Misdemeanors are punishable by substantial fines and sometimes jail time, usually less than one year.

I hope it's help