How can I be sure? Simply by citing the Talmudic verse itself; It’s self explanatory:
If you seek the origin of the word 'syrup' in Gentile sources, such at Merriam-Webster or Online Etymology Dictionary, you’re led astray to many other languages, but never to Hebrew that outdates them all.
So here you see:
1) It oozes from a tree.
2) The word שרף also comprises the verb to burn. You can see it's made for burning, inasmuch as it comes from a tree, as logs are the quintessential form of fuel. So these resins were created as flammable, but with an added benefit too, to yield a wonderful aroma - thus the source of incense.
(As for the same word “שרף” that defines a rank or type of angel, this too has to do with “burning”, probably in reference to their appearance or in metaphor, but I know too little to comment here.
This word may also relate to "serpent" (at least the first half of the word) - for the serpent's bite delivers a burning sensation, unlike the scorpion's that is cold.