Why do you feel the need to post it on Facebook?
It's no one's business what you do .
I live in Canada atm. How should I make it clear on Facebook I want to move to Nepal or India in a few years and get married, so accordingly I am not available for dating?
Are you thinking Facebook is a dating site?
... What Tiger Two said.
Also, dating does not mean you are going to marry that person. To the contrary, the majority of people who date do NOT get married.
The purpose of dating is to figure out what type of person you do wish to marry. So it is rational and reasonable to date lots of different people, before you decide to marry.