Learn Farsi: در این روتین، به این ضد آفتاب اعتماد می‌شود. - In this routine, this sunscreen is trusted.

In Farsi, the active verb "to trust" is اعتماد کردن, which requires the preposition به (you trust to someone or something). When making this passive (اعتماد می‌شود), Farsi keeps that preposition! This is called an impersonal passive. The sentence literally translates closer to "In this routine, to this sunscreen, trust is done."

Would the verb می‌شود change to plural if we were talking about multiple sunscreens?

No, it would stay exactly the same. Because of the preposition به, "the sunscreens" wouldn't be the grammatical subject of the sentence. In impersonal passives like this, the verb always stays in the third-person singular (literally: "trust is done to them"), regardless of whether the object of the preposition is singular or plural.

How does the compound word ضد آفتاب break down?

It literally means "anti-sun." ضد means "anti," "against," or "opposite," and آفتاب means "sun" or "sunlight." It is the standard Farsi term for sunscreen. You will see ضد used as a prefix in many other useful B2-level words, such as ضد آب (waterproof / anti-water).

Is روتین just the English word "routine"?

Yes, روتین is a direct loanword. It is very common in modern, everyday Farsi, particularly when talking about skincare routines (روتین پوستی), daily habits, or workouts.