When do we know we have built trust?

I was riding my bike along side my young daughter as she rode her bike. She is just learning now to ride her bike, and has spent most of her time learning confined to the sidewalk. On this bike trip, we venture for the first time out on the street! To a young child who knows not to go in the street, this is exciting. I am stressing the entire ride to use caution and stay close to the curb since this is the first time out there. Even on a quite neighborhood street we get traffic regularly, and she handles it well. So well, she begins to look around as comfort sets in that she has mastered her new world, the street. Every once in a while we come up on a car parked in the street. We have to leave the relative safety of the curb and venture further out in to the middle. Caution ensues. She quickly masters this too. She approaches a parked car, carefully pulls out and around and then dives back to the safe curb. Even this becomes routine and she reverts to looking around even though we are still in the dangerous area of street riding. Short cuts begin, distance from the curb increases, and I am forced to remind her that we still have to practice safety. She pushes the limit, waits until the last moment to move around the parked cars, but does it safely every time. Now just before we get back to the safety of our sidewalk in front of our house, there is one more parked car to go around. She is not watching, she waits until the last possible moment to go around…but it is too late. She hits the bumper of this parked car hard enough to firmly secure her front tire underneath the car.
Interestingly enough she knew a split second before impact that she made her mistake. She actually started to apologize to me for hitting the car BEFORE impact. As a parent I wanted to reach out and grab her to save her, yet at times even the desire is not great enough to overcome the mistake. I could not reach her in time.
Two things were learned that day WITHOUT anyone getting hurt or upset. My daughter learned that Daddy is actually right sometimes, and that his words are meant to protect. She is much more responsive to feedback from me, because she knows I have her best interest in mind. Secondly, she knows this because she trusts me that even when she makes a mistake I will not get mad at her. Rather, she knows I will help her succeed, grow and learn.
Can I, as a leader of people, follow these same principles in the professional work environment? Developing trust between leader and follower, practice open and honest feedback, and have the best interest of your people in mind? Absolutely! The resulting team performance is incredible.