I have - of course, everyone has - ny theory. Firstly, I think he was successful in his attempt. The lyrics are in a mood that, to me, he was asking something he already knew he would get eventually. And he didn't need that much - just a little oblivion...
The intriguing verse "don't want your money" appears, imo, because he did something useful for the angel of mercy and he does not want to get paid, as she might have offered. And it's the opposite way of transaction mede with a prostitute. If it was, HE would have to pay.
Nevertheless, I understand yontwocrowns feelings about unsecureness. I think that if we read the lyrics in a teenager or a unexperienced guy perspective, it makes sense. But still I think he was sure he would get what he wanted.
I love the song, I love the lyrics, but this thread made me compare, for the first time, "Angel of mercy" with "Night in summer long ago". The 1979 song uses a knight as a metaphor, while NiSLA, to me, tries to evoque the knight days to create a momentum, and at the same time can be seen as a metaphor of a fling, too. But I think his imagery evolved a lot in 20 less years, no?