18+ Seijo no Kaifuku Mahou ga Dou Mitemo Ore no Rekkaban na Ken ni Tsuite.

Long ago, I was fascinated upon seeing healing magic. But to be taught, you need to make a huge donation. I, who came from a normal family, could never afford it no matter how much I stretched my budget. Thus, I could only study and teach myself, quite desperately even. But around the time I reached the limit for what self-study could get me, I got to see a Saint first hand performing a charitable service using healing magic.

"Eh, that was Heal just now, right? It was only used a few times, and you’re already having trouble breathing, and not only that, your healing didn’t even do that much! You gotta be kidding me?"

(Source: Ohanashimi blog)