It can be difficult to tell if a cat loves its owner, but there are signs that showcase a cat's affection for its owner such as purring or meowing, erect tail with flat fur, lying on its back, kneading its paws onto its owner and rubbing its chin and body against its owner. A cat may perform these signs of affection towards its toys and other cats as well as its owner.
Owners should also be aware, however, that purring can also be a sign that the cat is sick or anxious, as cats will also use purring to comfort themselves when they are not feeling well. Meowing can also have other meanings and the "meow" is used by the cat as a way to communicate all feelings, from affection to "beware," as well as when presenting a catch, such as delivering a mouse.
When cats rub against their owners they are not just signaling affection, they are also signaling that this human belongs to them. Cats are very territorial creatures and they will rub the furniture, the floor, their toys and the door so that other cats know that these things belong to this particular cat. When cats are being affectionate, they are typically calm and will approach their owners gently.