I reported a rape, it went to court and he was convicted. It was very hard and seemed to drag on for ages. Have a look at the "my dh assaulted me" thread.
You need to be able to describe what happened to absolute and very clear detail; to say what you did, what he did and why you reacted/didn't react etc etc. You will need to describe the series of events before, during and after - time and time again. This will be compared against his version of events. You will also be expected to remember what you were wearing (if it was a one off occassion)and what he did re clothes etc. IE, You need to be detailed and explicit. Oddly, it gets easier and easier to say the more times you say it. By the end I could give a mechanical account of events; it all felt very impersonal.
There are only 2 of you (usually) who know exactly what happened, as rape tends to be behind closed doors. Like a dirty little secret. This is why I went ahead with it - I knew what he had done and that he was lying and thought he could get away with it. But you have to be very, very sure in your mind about your side of the story and be ready to have it pulled apart. He will be seen as innocent and it is up to you to prove that he isn't.
BTW, I did not report the rape straight away.
HTH. Contact me if you wish.
I have also changed my name.