i think when you meet people who really care it's obvious. I've been dating someone now and we live half an hour apart. he always drives to see me without complaining. from past experiences if a guy didn't feel like it he wouldn't bother.effort speaks in volumes. so does respect and compliments.
If a guy cares, it's pretty obvious. He shows it in every way...However, when it comes to women, we men can never know :P
One big thing I've noticed is when they try to do anything they can to make you smile (they want you to be happy).
How do you know if someone cares?
I guess people like the attention of having someone after them but how can you tell that they truly like you for you?