Is it permissible to use assertive language when stating the advantages of a product, such as saying: "The ointment eliminates acne" instead of "The ointment helps to eliminate acne," and is it permissible to claim that its results are guaranteed, based on the experiences of most users?

Truthfulness is obligatory when promoting, advertising, and describing products, based on the Prophet's (peace be upon him) saying: "The two parties to a transaction have the option [to annul it] as long as they have not parted. If they are truthful and explain [the defects], they will be blessed in their transaction. But if they conceal [defects] and lie, the blessing of their transaction will be effaced." It is not permissible to state something contrary to the truth, such as definitively claiming that a product eliminates acne and its results are guaranteed. Rather, one can say that it eliminates acne according to many who have used it, or that it is beneficial for its treatment. Truthfulness and clear explanation are causes of blessing and reward, while deception and fraud are causes of the effacement of blessing, loss, and sin, due to the Prophet's (peace be upon him) saying: "The truthful and trustworthy merchant will be with the prophets, the truthful, and the martyrs."