You are missing no updates, mon frère. I indeed mean the scene that takes place right after accepting it. I fear I lack the skill to say what I mean by "truly understand what the Oath of Rings means" without just explaining my thought process; and that'd be tedious and maybe even cringe.
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Anyway, here's my thought process.
After you accept the pact, this interaction happens:
You: "Did you expect me to go back on my word now that we are putting consequences on the table?"
Asterion: "Yes, I did. I - I cannot, could not, imagine a Master accepting conditions so absurd."
You've been a saint. You saved the guy, you treated him well (more like decently), you will help him with his thousands-of-years-long project; and yet Asterion said that. It was then that it clicked for me: you are not the first kind person to be a master; hell, you might not even be the nicest person (not at this point anyway).
To the MC, this is like a magical situation of epic proportions; to Asterion it's another piece of an endless cycle. A nice, special piece, but one can imagine how many times Asterion has faced a nice master that turns sour or is followed by an evil one. That will create a sense of mistrust in anyone that bears the title. What this interaction means IMO, is Asterion getting hope that things will be truly different this time. An idea that will come true eventually, since we know they'll be in a romantic relationship.
As to what it means regarding the gods, I have my theories on them which I cannot tie with confidence to anything I said so far. Except, how I said the rings are ominous foreshadowing.
Again, I think you should make the options you think are right. Also, I'm not the master of all truths; I didn't even get max ranking at the end of the build.