Sorry if I am offending in any way, I just think I have to tell you this.
The secret I swore to take to the grave is : someone trusted me to be the only one to know the same thing happened to her.
Since the age of 4, she suffered many issues. Still, she managed to bear with them and was successful in life. She is a great person. Mainly she has now relatively small difficulties with trust, self-esteem, body image, love and being loved (also esteemed), and sex, obviously.
Over time, it built up to a very resilient temper. Whatever shit life threw to her, she would cry to herself (and recently to me -as a friend-), but endure about anything. She is perceived as "emotive" by most people, but also as "brave" because she ultimately overcomes it all.
When she told me what happened to her and how it influenced her life, she made me swear I will tell absolutely no one. I guess I respect my pledge as you are all "no-ones" ?
It was a very important moment for her. The feeling of guilt that she had as a cruel company (that's her term) for virtually all her life was confronted with my reaction: nothing but compassion and support.
There was no fault of her own, and for the first time she could not only tell it to herself, but see it on my face. In the few hours afterwards we were a bit awkward, but from the day after things began to change.
It has only been a few weeks, but her attitude towards life has changed slightly. To put it simply she does not endure difficulties now, she turns everything she can into an opportunity. She claims her share of the world and her share of happiness as well.
In two or three weeks she got a contract for a better job after her PhD, finished version one of her thesis manuscript, solved her immigration issues, ate better, got her sentimental life sorted (a little), and got her first orgasm in her life (which may sound odd but is actually a big deal, when you think about it).
All in all we talked about it exactly once, for an hour or so at most. I promised I will not be the one to bring it up ever again as well as tell no one.
I am a man in my thirties, and I cried like a baby when she texted me "One talk changed my life. Thank you." a few days afterwards. As a matter of fact, I am crying again typing this story.
TL;DR: if and when you feel you could tell someone, it could change your life as well as this person's life. Even if no police gets involved.
footnote: not a native English speaker, sorry for grammar