It is natural to miss someone who had been in one's life romantically and no longer is.
As far as whether or not there is hope, that answer would be only something she can answer. Of what you have posted, it seems that it had been quite some time ago and that she had indicated that she would like to remain in touch but not be romantically involved. Your desire to have her back may be incongruent with hers and if she senses that she may feel let down or that her wishes were not respected.
With time peoples feelings change which too is normal. Although you had dated other women, perhaps you are unconsciously trying to compare them to her and that is one of the reasons it had not worked out with another woman. Ultimately what you are feelings is a result of your thoughts. If the thoughts change, it is possible for the feelings to change and for you to move on and be happily involved with another person. For whatever reason, the prior relationship had ended.