yes! excellent reference! i also want to point out that girl puts the desired outcome in the question which is important. in opulens' solution you only get to learn about the guards, not about what's behind the door.
True, heaven is never actually promised. That could be part of the lie as well, you never know when they start lying.
Also, the robots are listening, this turned up too:
There is an easier solution than the one most commonly known.
You can simply ask either guard "Does the guard on the heaven door always tell the truth?"
There's yet an even easier solution, presuming you're learning the riddle from the guardian that's being truthful and spending your question validating.
Evidence, and proof.
Trust, but verify.
Or choice, chance and damn the consequences.
Back to unwrapping the words and the lies. The wood witch scoffed at the idea of finding truth there in that space. If the signs and symbols are to believed then Odin's illusionary rune should cast doubt on what was experienced. Maybe if the lies can be peeled away what's left will be truth?
“Every blessing ignored becomes a curse.” - The Alchemist