It’s easy to assume the other person wants the same thing as you in a relationship, which is not always so. As people begin to mature they want something tangible out of life and this includes a relationship, but because they want it doesn’t mean they would get it.
Most times people already invest so much in the relationship before they realise their partner isn’t taking it as serious as they are. It’s not like there is a club or bar where people looking for serious relationships hangout neither is it written on people’s faces. It’s all trial and error which can take your time, energy and money before you realise it’s not for you.
There is community of people looking for serious relationships online, people who don’t want random or casual dating. This is the best way for you to meet people in your area who are on the same page with you and want the same thing you want which is to find love in a serious relationship.
People on other non specific dating sites may not be looking for a serious relationship like you, so why not search for it where the people you want are concentrated. Dating doesn’t come any easier than that.