Eslam-
Hundreds and hundreds of people are denied visas- it shouldn't be a surprise (sorry).
Someone who is young & single, without a lot of financial or emotional ties to their country will most likely be refused because Canadian immigration assumes that without ties to your country, you will not return there at the end of your allowed visit to Canada. It can also depend on the person who sent you a letter of invitation- was he/she a refugee?
Anyway, of course seeking out a Canadian citizen or permanent resident to marry you is completely illegal (under IRPA) and is not a good idea at all. Immigration officers can easily smell a marriage of convenience.
Since you say you are well-off and well-educated, you should wait until you have some working experience and then apply as a Permanent Resident under the Skilled Worker Class. Unfortunately (depending on how you see it), the rules have recently changed and you might not qualify. Good luck.
http://www.cic.gc.ca/english/immigrate/skilled/apply-who.asp