I(23F) just got accepted to a master program at U of R and is currently looking for an off-campus house to rent. After posting on Kijiji, an old couple (whose name is Andre and Sandy Ullman) contacted me, saying they have a room for $650 and is at a reasonable distance from campus that can be mine if I send them a small deposit. The couple said they are approved to be host family by the school I will be attending, meaning their house is fire department approved, they know how to make an international student more comfortable, etc. We talked for about a week for details like utilities and other students staying at their house; they sent pictures of the room, which is a decent room with one bed, one desk, and one closet. They even sent me a letter from their current host student about how sweet and nice the house is. Overall, they seem like a nice couple and the deposit is indeed a small amount ($50). The damage deposit is $300. I pay $50 first to keep the place in case I won’t show up then pay the rest when I show up.

So I contacted U of R asking whether Andre and Sandra are truly hosting family or not but the school refuse to give out any information regarding this subject.

The problem is I'm not in Canada right now and I don't want to find myself to a situation where I arrive in Canada for the first time with no place to live or being robbed by someone when I go to their house. If I accept the offer than it turns out to be a fraud, I would be homeless for at least three months until the dorm open again. I know no one in Canada so it would be really bad.
My question is there any legal document(s) I can ask the couple to provide to ensure what they said is the truth or a contract or something. I know it isn't the best method but maybe it can grant me a bit piece of mind.

Thank you in advance and sorry for my English.