She needs training. It won't happen magically

You need to take the diaper off and let her experience. Otherwise she will know the diaper is there and she will have dependency. At 5 she is more than capable of holding it. You just need to explain to her well and allow 'accidents' to happen. At this age it should not take more than a month (even if she wets her bed every night in this month) to be trained.

Of course if she has any medical reasons you need to take her to the doctor to check it out. But it's probably not the case here.