There are different websides, offering flats / appartments / houses to have a look, as well in local newspapers. But the best way is having connections. And never pay in advance! An option is, to ask a real estate agent with good connections, but then you have to pay the agent.
You only have to share, if you apply for a room in a WG (shared flat). But this is always mentoned, as usually those people living in the WG search for a new member in their WG. If this is not mentioned like "one room in a WG of three" (ein Zimmer in einer Dreier-WG) the ad will be for a whole flat / appartment / house.
If there is a landlord, this will get to know you. At least you will have a video call, if not a visit to see the flat in person. And any payment will be done on a German bank account. No one uses foreign banks, paypall, wire or things like that as a proper landlord.
Hey costandina my niece looking for hostel she is in Kenya she is coming for her masters in Germany how do contact you for help am here in Germany but on my returnie process back to Kenya early retirement healthy issues pls contuct or Facebook side. Wishing you merry Xmas n happy new year.