"This is a sweet peach."
Translation:זה אפרסק מתוק.
The translation cannot be "This peach is sweet", because that would be "האפרסק הזה מתוק", right?
On the other hand, "This is the sweet peach" would be "זה האפרסק המתוק", right?
"This sweet peach" ≟ "האפרסק המתוק הזה"
Finally, is there any meaning at all in the construction "זה מתוק אפרסק"?
This construction might mean "this is peach-like sweetness", when the אפרסק is used as a part of an adjective, and you should note that a hyphen would be added in that case (מתוק-אפרסק). This construction might not be popular with most words, but combinations like לבן-שמנת are used sometimes, so you should definitely be somewhat familiar with them.