Learn Farsi: پرستار در مهدکودک بچه‌ها را نمی‌ترساند. - The caregiver does not frighten the children in the daycare.

The basic verb for 'to fear' is ترسیدن (tarsidan), which is an intransitive verb (it doesn't take a direct object). Its present stem is ترس (tars). To make it a causative verb meaning 'to frighten' or 'to make someone fear', we add the infix ـانـ (-ân-) to the present stem. This gives us the new stem ترسان (tarsân), making the full causative infinitive ترساندن (tarsândan).

Because it is a causative verb, does that change how we treat the object in the sentence?

Yes! When you use the regular verb ترسیدن (tarsidan), the subject is just afraid—there is no direct object. But the causative verb ترساندن (tarsândan) means 'to frighten [someone]'. That 'someone' becomes a direct object. Here, the specific direct object is بچه‌ها (the children), so it must be followed by the definite object marker را (râ).

How do the prefixes stack up to make نمی‌ترساند negative?

The verb is in the present continuous tense, which uses the prefix میـ (mi-). To make it negative, we add the negative prefix نـ (na-). When نـ is attached right before میـ, its pronunciation shifts to 'ne', giving us نمیـ (ne-mi-). Then we attach the causative stem ترسان (tarsân) and the 'he/she' ending ـد (-ad).

I usually see پرستار translated as 'nurse'. Why is it 'caregiver' here?