The Charmin commercial appeals to pathos effectively because it makes you laugh. The idea of a bear using toilet paper in the woods and having "pieces left behind" evokes humor to make you remember the toilet paper brand. It also uses pathos because you feel warmhearted towards those bears because they look cute and cuddly.
The Charmin commercial appeals to logos effectively because it gives examples of how well the toilet paper works. We see examples of the "other" toilet paper, which leaves pieces behind and shows us that the other brands aren't good. But the Charmin toilet paper doesn't leave pieces on the bears' bottoms. Also, they show a comparison between charmin toilet paper and the "other" brand, where they pour water on the toilet papers and try to use them to drag a weight of some kind. The other brand tears, but Charmin holds together.
The commercial creates trust because it is a brand that we all recognize. The emotions and the logical proof that the commercial shows draw you in and prove to you that it's a good product, so you can tell that the creators have done their homework. That builds trust because it lets you know they really care about this product.
In conclusion, the Charmin bears commercial uses rhetoric effectively because it uses the three appeals, ethos, logos, and pathos to make you remember the brand. The idea is that you will be in the grocery aisle and see Charmin toilet paper, and then you remember the Charmin bears and that it is a good brand.