Moody guys who refuse to commit are no longer the type that women are trying to lock down. That stereotype has become tired and now men who commit are looking much more attractive. The ladies have realized there's no point in trying to convert someone who doesn't want to dedicate themselves to a loving relationship, so if you appear non-committal, it's going to end up being a problem for you.
Being 100 percent ready to say "I want to be with you exclusively" is sexy and most women will love hearing those words spoken to them. We've got enough going on in our lives and don't have time left over to chase boys who simply aren't interested in a commitment. We're not necessarily talking about marriage here. Just an acknowledgement that you're moving forward in life together.