Like I said, this is not an untouched image but the rays are real, though emphasized through contrast adjustments. I am always honest about that but like your comment on my other image, it becomes a pointless discussion when people don't believe it. either way, honest opinions are always appreciated on my side and I respect yours.
The circumstances have to be just right and I often go out there and find sunrays that are really weak. getting up early on a day when it is promised to get very warm gives you the best chance of strong sunrays in my experience. I do use a tripod and long shutterspeeds and combine them if necessary with other exposures in postprocessing but most of the time I use a single exposure and enhance the contrast in PS. Some photographers use dodge and burn as well. That's all there is to it.