Hi. We had the same sort of problems with our daughter. We eventually decided to redecorate her room but let her help and choose everything she wanted. We did most of it using left over paint and it only cost us some new bedding. The condition was that she had to sleep in her own room.
This was two years ago now and she has slept happily in her own room since. Takes a while but eventually found out that the princess border scared her when she woke in the night.
Try playing her favourite music in the day. The same music everyday. And then when she so used to it try it in her room. She will be relaxed with it. It may help her to settle.