Pour exprimer quelle est l'intention de l'auteur du document étudié, (ici une publicité) on peut dire :

• The aim / the purpose of this advert is to make us buy the product.
• The advertiser wants us to buy the product.
• The advertiser aims at making us buy the product.
• The advertiser's goal / objective is to make us buy the product.
• Through this advert, the author is trying to make us buy the product.