Learn Farsi: تو نور امید در این تاریکی هستی. - You are the light of hope in this darkness.

This is a classic Metaphorical Ezafe (Ezafe-ye Tashbihi). It links the metaphorical image, nur (light), to the actual subject being described, omid (hope), using the unseen "-e" sound. Instead of just saying hope is like a light, this structure directly equates them to mean "the light of hope."

What would happen if we reversed the word order to omid-e nur?

The meaning would completely change to "the hope of light" (for example, hoping that the sun will rise). In a Metaphorical Ezafe, the poetic image (the light) almost always comes first, followed by the Ezafe, and then the abstract concept (hope) it is describing.

How is the word târiki (darkness) formed from the base word for "dark"?

It is formed by taking the adjective târik (dark) and adding the noun-forming suffix -i. This is a very common way to turn adjectives into abstract nouns in Farsi, similar to adding "-ness" in English. For example, khub (good) becomes khubi (goodness).

Why does the sentence use the full verb hasti instead of just attaching a short verb ending to the previous word?

While everyday spoken Farsi often shrinks the verb "to be" into a suffix attached to the end of a sentence, using the full, independent verb hasti (you are) adds emphasis and weight. Because this sentence uses a dramatic, poetic metaphor (nur-e omid), the full verb matches the elevated, slightly more formal tone.