Meanings of own truthfulness in English

A very satisfactory thing to be able to say of yourself, if you believe in your own truthfulness.

She taught him to be truthful, but her lessons were not half so forcible as her own truthfulness.

And then she stood accused before her own truthfulness of having covered up her blush by a disclaimer that had nothing to do with it.

Of her own truthfulness to her friends, which led her frankly to speak to them of their faults or dangers, her correspondence gives constant examples.