The method for completing a covert quest is simple.

You enter the room, approach the NPC who holds the quest, and start a conversation. Then, the dialogue proceeds, and once the conversation ends, the quest is automatically added to your quest log.

The tricky part is that no notification pops up when you receive the quest, so sometimes you won’t even realize you’ve accepted it, and if you continue with the story without noticing, the quest will end up failing.

In reality, there’s no system window like that, so I had to rely on my memory to keep track of …