I feel like I truly repent when I feel bad for something I have done and then decided to fix the problem. If I did something to one of my sisters then I need to apologize not only because mom and dad said so, but because I will feel better after I am no longer fighting with them over it.
Take a look at this picture. It shows a depiction of a young boy being tempted.
We all sin, it is our job to do our best to not sin, and when we do we repent for it.
"IT IS BETTER TO PREPARE AND PREVENT, THEN IT IS TO REPAIR AND REPENT."