What would you do if you found out your child had been molested?

Suppose it happened quite a long time ago and that they never told anyone, but you come to find out they are secretly seeking therapy for it now.
Would you wonder why they haven’t told you? If it is a fear of your reaction, or if it is that they are feeling ashamed?
Would you let on that you know they are seeking therapy? Would you just keep silent and wait for them to come to you when they are ready? Or would you tell them that you have learned what happened?
And how? Would you drop hints or would you just be open and honest with them?