How do you know your animals love you?

It depends on the animal, doesn't it? If it's a dog they will show they love you by greeting you when you come in; following you around the house; pestering you; licking you; and even snuggling with you. If it's a cat perhaps they will greet you by rubbing against your leg, or purring when you pet them. They are independent so they simply keep to themselves but love you none the less.