You can say “THE SUN SETS IN THE WEST.”
Or you can say, “SUNSETS OCCUR IN THE WEST.”
You can even say, “THE SUNSET OCCURRED IN THE WEST.’
SUN SETS is correct because it is referring to a single sun, you could use ‘A’ or ‘THE’ to make it so.
SUNSETS is correct because it is referring to plural.
But SUNSET still needed a verb since it is a noun, where as SUN SET is the noun and verb. You can’t say THE SUNSET WEST or THE SUNSETS WEST but you can say THE SUN SETS WEST.
I probably use sunsets too often in my writing. Between them and a sunrise, they are things I’ve experienced, and have a feeling associated with them. Not all are breathtaking, but they carry a pretty universal symbolism to them. However, I always prefer to make the sunset active. Like “THE SETTING SUN CAST AN ARRAY OF ORANGE AND PURPLE.’
Technically, I could/should write “THE SUNSET CAST AN ARRAY OF ORANGE AND PURPLE.”
Much like music, the slightest change creates a different tone. Every musician (that’s not a drum machine) plays differently, how will your sunset be cast?
WELCOME TO THE JIREVERSE 