Everyone is right, no one can tell you how to get over fear, just do it.
The way I progressed over the backflip is :
1. Doing it on a slope, then hurt my knees lol.
2. I learned it the proper way and on leveled ground , then backfliped on higher platforms.
3. Learned how to do one foot backflip(for wall flip) off a platform.
4. I run and land on a short platform, then as quick as I can do a one-foot backflip.
5. then do it on a wall. Step on the wall (like a platform), then one-foot backflip on it.
6. If you can do a wall run, then try 2 steps and one-foot backflip lol.
The way I got over my fear, and tricking myself into commiting is using visualization. I pretend there is a big mat behind my back that i'll land on softly on it (while on grass lol), and I fully commit to it full force.
Jump up,at peak, then rotate. If grass is too big a deal, just do it in a pool.
I have no spotter, gym, nor mats. I just went out there and busted my ass enough to learn lol.
thats what I did to get over backflip and wall flip fear, but I recomend to be familiar with a standing backflip or layout before the wall flip.