Learn Spanish (Latin America): Se dice que el romance desató un escándalo. - It is said that the romance unleashed a scandal.

The phrase se dice que reports a claim, fact, or rumor. Because it just passes along information without inherently expressing doubt, denial, or emotion (unlike a phrase such as se duda que, which means "it is doubted that"), it is followed by the indicative mood.

Is se dice considered the impersonal se or the passive se in this sentence?

It acts as an impersonal expression here. Even though we translate it using the passive English "It is said," the Spanish structure followed by a que clause has no specific grammatical subject. It simply means that people in general say it, much like "They say that..."

The verb desató translates to "unleashed." What is its literal meaning?

The verb desatar literally means "to untie" (des- means "un-" and atar means "to tie"). Just like a tied object being let loose, untying something metaphorically means "to unleash" or "to spark" sudden events like a scandal, a war, or a storm.

Why is the preterite tense used for desató instead of the imperfect?

Unleashing a scandal is a sudden event that marks the start of the chaos. The preterite desató captures this one-time completed action. Using the imperfect would mean the romance "was unleashing" a scandal over an undefined continuous period in the past, which sounds unnatural for the initial breaking of a scandal.