* They say what they mean, and mean what they say. There's no ambiguity or deception in their communication.
* They follow through on their commitments. They don't make empty promises or back out of agreements.
* They have integrity. They are honest and act ethically, even when it's difficult.
It's a positive character trait that emphasizes honesty, reliability, and integrity.
The phrase can be applied to both men and women, but it is traditionally used for men.