"Vala jaeho gevivī rijas."
Translation:The man praises the god's beauty.
In the real world that form is used by people who believe in monotheism. In the books the faith of R’hllor comes close to monotheism (or Zoroastrian-style dualism), but since they call their god the Lord of Light (Āeksio Oño) and not "God" (Jaes), it's hard to say whether they'd phrase it that way.
Gramatically it should be OK, I think. There's a bunch of complications in English regarding "zero article" (the absence of an article) when "the" and "an" are normal (like saying "Mother likes cakes" vs. "The mother likes cakes"; suddenly there's an implicit "my"); but, in my opinion all of "the", "a" and zero article probably collapse under the same structure in HV. Still, as of today most exercises on Duolingo don't accept zero article as an answer; I'm not sure whether that's an oversight.
Do you think this could also be "The god's man is praising the beauty."? I'm still getting used to working out who the possessor and the possessee. In this sentence, could the man be the possessee instead of beauty?
I think so; we have an example with voktī Rulloro which translates to "priestesses of R’hllor". However, the possessor usually comes first, so the normal interpretation would be the god's beauty and not the god's man.
One case where the possessor often comes last are titles, like Daenerys Jelmazmo (Daenerys of the Storm).