Sounding frank, honest, and sincere is, of course, a rhetorical strategy in itself, known from ancient literature as parrhesia. It’s often employed by liars.

Cathy's lies were never innocent. Their purpose was to escape punishment, or work, or responsibility, and they were used for profit. Most liars are tripped up either because they forget what they have told or because the lie is suddenly faced with an incontrovertible truth. But Cathy did not forget her lies, and she developed the most effective method of lying. She stayed close enough to the truth so that one could never be sure. She knew two other methods also -- either to interlard her lies with truth or to tell a truth as though it were a lie. If one is accused of a lie and it turns out to be the truth, there is a backlog that will last a long time and protect a number of untruths.

Of course, the liar often imagines that he does no harm as long as his lies go undetected.

She looks honestly upset, but then, I’ve learned that I can’t read her. The problem with a really excellent liar is that you have to just assume they’re always lying.

A lie carries a weight that is exponentially higher than the truth. It’s weight will retard growth directly in proportion to the area lied.

Politicians are people who learn not to blink, when they lie.