Truth: that which is in accord with fact or reality (Definitions.net). If reality is truth, then "perception is reality" equates to truth, and resides in the eyes of the perceived. We each have a truth as we understand it to be. Yet, where there is a disconnect, we must view it through a growth mindset; recognizing another's perception is as much their truth, as our perception is our truth.
The disparity of the truth, or difference of opinion, has the power to generate hostility and anger. As this builds, one's level of defense intensifies as one tries to prove their truth. When one's truth does not "win" in the view of others, we start seeing exaggerations of the truth and even lies; which often leads to greater hostility as they now start protecting not only their perception but also their character from the truth being revealed.
Confidence comes when we hold true to our truth. Appreciating the disparity of truth allows us to avoid defending ourselves in the vain of someone else's truth. We must be comfortable knowing that someone else may see things differently, and afford them the opportunity to do so.
With truth comes confidence and understanding, with deceit comes hostility and lies.