The only way to repair broken jewelery is to silver solder it. However, it should be done by a professional because some metals won't take the heat needed to do the job. A professional jeweler will beable to tell if the pin can be repaired this way. If I was going to use glue to do something like that I'd probably use a good grade of epoxy glue, such as that used to fasten the head on a golf club. It would be much stronger than super glue.