I'm with Kiya in that my expectations are made known at the beginning of the relationship... that I am dating for marriage, and there will be no lengthy "dating" periods happening with me.
Then, I sit back and watch how the relationship unfolds. If HE is the one to continue to move things forward, then I feel good that this man is equally marriage minded.
If by a certain point (6-9 months), the "M" word isn't even discussed, then I know it is time to be out... I won't say much to remind him of my expectations or anything like that... I'll just start backing away and preparing to move on. And if he starts wondering why, I'll simply say that it's clear we aren't on the same page. And while I wish him well, it's time for me to move on to someone else who is clearly looking for a wife, and not a girlfriend.
I don't consider this pressure at all. He clearly has a choice, and if his choice doesn't fit with mine, I leave. Many MEN say that a man knows if he wants to marry you VERY early on (not necessarily saying he will propose, but he will know) and then he will move in the direction of marriage sooner rather than later... and the woman in that situation will never have to wonder if he's going to propose or not. Because he will.