Don't tell them to forget about it. Don't say, "it happened a long time ago, why does it suddenly bother you now?" Healing can take time and some people block or try to forget traumatic events. This is a way of coping with what has happened. Remembering can be triggered by events such as the birth of a baby, a T.V. programme, marriage, changing job, starting a new relationship etc....
Don't ask them why they didn't fight back. People can freeze when confronted with a terrifying situation.
Don't ask why they didn't say anything sooner. If it happened when they where young they may have tried to tell but been ignored or disbelieved. They may have been threatened or been too frightened to say anything. Most people do try to tell someone at some time.
Don't tell them what to do. They need to be in control of their own decisions about matters that affect them. You can help them to explore options that are available to them.
Don't pressure them into doing, or talking about things they are not ready to face. When they are ready they will speak.
Women are often afraid of how other people will react to what has happened to them, they may fear not being believed, embarrassment, having their experiences minimised or trivialised, even fear rejection. Women often fear well-meaning, but ignorant questions such as: "Why didn't you tell me before now?" "Why didn't you scream?" "Why didn't you tell someone?" "Why don't you report it to the police?" "Why did you (encourage him / wear that skirt / walk that route / etc.)?" If you do not understand why a woman is behaving in a particular way, or is reacting the way she is now, remember that this is YOUR problem, NOT HERS. Do not badger her with questions or ask her questions, which you are not sure, whether she will want to answer; read a book instead.
The woman may have her own questions about what has happened to her and may want to explore these with you. It is very important that she makes up her own mind and finds her own truth about what has happened to her and makes her own decisions from it. Sexual abuse and violence leaves women with feelings of powerlessness and loss of control about their lives. It is important that people do not take over, without consulting with the woman about what she needs in the situation. Confronting the perpetrator, phoning the police, or making a medical appointment 'on her behalf' may make matters worse, you can best help by listening to her and asking her or checking out what she wants; do not tell her what YOU believe she OUGHT to do; explore her options with her.