Perception is reality to the average human. That is deeper than it sounds. It means that every single person has their own version of "reality" or what they would call the "truth" based on their perceptions.
With time and a little practice, you will find yourself "speaking wisely" without consciously thinking about it. You might be amazed at the powerful, assertive ways you can communicate within the frame of these six guidelines.
We can't possibly know what is going on inside someone else's head and thoughts -- even though we know someone really well. It's always better to check. And the best way to check is by asking questions.