my star jasmine is dying inside
There are leaves and flowers outside, but dead branches on inside. The one jasmine next to it is full and healthy.
The fact that the plant next to it is healthy kind of rules out cultivation issues such as water, light, soil, etc. Two things occur to me; one is that the failing plant is simply not a strong individual. In my experience some plants just don't make it, no matter what you do. The other thought is that a disease may have started. You'll want to get an analysis of the possibilities to protect the other plant(s). Take some samples of leaves, stems, and roots/soil to the nearest extension service for advice. This link will help you find the nearest one: https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm