I'm not sure what exactly you mean by training emotions. However, there are some VR tools specifically in Exposure Therapy that try to elicit emotional response. Some of them also act upon those response. One commercial tool is Psious (https://psious.com). Another is a research project called PATRONUS which aims to improve VRET by providing a blended care solution. This solution includes personalised adaptations of the VR environments as well as feedback based on physiological responses.