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The Nose Knows is a superpower, but for supposedly ordinary characters knowing the smells they logically shouldn't, umm. Things Are More Effective in Hollywood ?
For the other one, start from Smells Sexy
Memory Trigger. It's Truth in Television that Olfactory memory
is one of the most intense and resilient types of memory in most people, even if we don't consciously realize it. One of Marcel Proust's stories provides a stock example that even appears in psychology textbooks, where the smell of a particular type of cookie triggers a rush of intense childhood memories for the narrator.
It’s not so much about scent memory, more about how scents are always clearly described in fiction - even if it doesn’t make narrative sense for the character to be able to so clearly identify the scent. I’ve got a sensitive nose and I’ve worked for years on memorizing common fragrance scents, but I’m a little crazy like that, and most characters in fiction are not.
Creator of Heroes of Thantopolis: http://heroesofthantopolis.com/Exactly, but it would be one of the Acceptable Breaks from Reality - something a person in the field can tell wouldn't work, but it smooths the story down, saving on explanations and setup. I have this with characters learning languages from watching television - sometimes it harms my suspension of disbelief.
I agree it’s an Acceptable Break from Reality, just not sure if it deserves its own page. What about the second trope? Thinking about it more, it’s less about the scents being identified and more about how a character identifying another’s scent is a tell that they’re the love interest. Not sure that lines up exactly with Smells Sexy?
Creator of Heroes of Thantopolis: http://heroesofthantopolis.com/Well, in Archipelago Riley is given Alice's scent by Dragonfly and told this is the scent of his True Love, and sure enough, he's head over heels as soon as he actually meets her. But we actually don't have this trope listed there.

Two scent-related tropes I’m looking for here.
One I imagine may be a missing supertrope, where characters in fiction can perfectly identify scents, no exceptions. This is an acceptable break from reality as books, tv, ect., cannot otherwise express scent to the audience. So when a character says their love interest smells like sandalwood, even if they live somewhere without sandalwood trees and before scents were synthesized and commercialized and thus shouldn’t know that scent, we trust that the love interest does in fact smell like it.
The second is a Trope that fits underneath, I’d call it “Attraction Smell Tell”. This is when a character notices the smell of someone they’re attracted to. It’s very common in romance novels, where the MC catches the scent of their love interest as they’re starting to show interest in them. I think at some point it was a subtle way of indicating that the MC is subliminally attracted to someone, but at this point it’s so widespread that it’s no longer subtle.