In this era, the general rule is who asked who out. The person who did the asking out is the one that pays.
However, although this is the most appropriate scenerio, most women in Toronto still prefer men to pay.
Depending on the type of female you are dating, paying means different things.
If she is a GoldDigger, than men should pay all the time because she only cares about how much you spend on her, not really about you. These types of girls should be dumped and not worth anybody's time.
If she likes taken care of and special treatment, then paying means she got special. In fact, she would not want you to pay unless if she likes you as a potential boyfriend material. This is a common mentality women take on.
Another type is she wants you to pay because she doesn't have money or can't take care of herself. She is totally useless and depends on her looks to live.
Another general norm is that men usually start off paying as the act of pursuit, but once when the relationship gets serious, she should will chip in.
One thing that you should note is whether she appreciates your generosity. Are you getting any physical rewards? Does she offer to pay anything? If she does, then great and you are heading in the right direction.
If she doesn't, then she doesn't care about you and only care about your money and how much more she can leech off from you. In this case, just dump her.