New DM here; our group is in the very early stages of a D&D 5e campaign. My players have been hired to provide security for the wedding between Lord P (whose nefariousness was established in previous sessions) and Princess Q (the players know she is widely beloved, but little else). I've tried to drop copious hints about what's really going on: that Princess Q is also a spy whose goal is to learn what Lord P is up to.
My problem is that I truly can't tell whether the players have figured this out or not. No one has come out and said "oh, she's a spy!" But it could be that they consider this obvious enough that no one has bothered to repeat it out loud. (Right now the party is focused on figuring out whether Princess Q is in immediate physical danger, and from whom; this additional knowledge wouldn't necessarily have affected their actions yet.)
Knowing that Princess Q is a spy isn't crucial for the plot, but it would add interest to the story and could affect the party's choices later. I think the players would enjoy deducing this fact for themselves rather than being told straight out, which is why I haven't been more direct; it also wouldn't be realistic for these low-level characters to be told explicitly about high-level espionage operations.
I ask the players for a summary at the start of each session, to remind us of what's happening and let me assess what they think is important. But I don't think I can ask more specifically without giving things away if they haven't in fact figured it out. ("So, what do you guys think Princess Q is up to?" is pretty suspicious.) How can I probe what my players have and haven't figured out, in a way that isn't too obvious?
Best Answer
Before I answer, I would ask you, as a DM; What difference does it make?
What would you change in your game if you knew the players knew that Princess Q was a spy? Would PQ change her tactics? Would PQ know that the players know? How did she find out since no one is outwardly saying anything in- or out-of-character?
To me, it sounds like what you really want to know is if your DM'ing skills are being correctly interpreted by the players. You say that you've dropped hints. But since no one is saying "She's a spy", you are curious if you're playing your NPC's correctly.
I could be completely wrong, but that is what first comes to mind.
With that said, the best way is to ask the players about ALL the NPCs in general.
Don't say, "So what do you guys think of NPC X?" Ask for more global feedback, such as, "I've tried adding some back story to a bunch of the people you meet so they are not so two-dimensional. Is that coming across?"
If they can't tell, then it's time to figure out a new way to get information out. Maybe they aren't looking for subtle. Maybe they aren't invested in the story line enough. Maybe they see the clues but think they point to someone else.
If they say they can tell, ask for examples. Someone will likely pipe up about PQ and you can go from there.
I ask for that kind of feedback all the time. In a session I ran a couple months ago, I physically handed them a bunch of notes/scribbles from the local scholar on how to solve the puzzles in the dungeon they were about to explore. Some I made obvious, some more subtle, and a bunch of non-related drawings. After it was all over, I asked how and if the notes helped. Most were figured out, some didn't make sense until I told them, and even some of the "fake" notes became part of the adventure as they tried out new things.
In the end, that feedback helps me shape future sessions as I know what they pay attention to.
So just ask for feedback about the adventure, specifically the NPCs, and see what they have to say.