For rent a house,
You can post or ask a Vietnamese friend to post information on some real estate groups on Facebook, i think. Some keywords to search: Bất động sản tại Đà Lạt, Nhà đất tại Đà Lạt,...
Using websites/applications: batdongsan.com.vn, nhachotot, homedy,..
Using a real estate company in Dalat.
Or just go to where you want to live and ask the people who live around there.
I don’t have information in Dalat, but in Hanoi, maybe you need to pay 10.000.000 - 50.000.000VND for per month.
Hope this helps ~!