Luckily for us, dogs brains are very similar to humans and the part of the brain that controls the experience of emotions is certainly present in dogs.
So the first point to make is that dogs do have the ability to love. As for whether they love you– do they show happiness when you arrive home? Do they want to be close to you? Are they excited when you want to spend time with them, for example, by going for a walk or playing a game? Do they stare at you looking for visual clues on how to please you?. If the answer to most of these is yes, then there is a very good chance your dog loves you. If in doubt, if you love your dog, it is very likely they love you right back again.