I am looking for a website to look for accommodations in Japan but Idk what is safe.

I am planning to study in Japan for a short-term course, one of my current issues is looking for accommodations since I don't know if it's legitimate or not.

Currently, I found NASIC:

https://749.jp/international/en/

And OAKHOUSE:

https://www.oakhouse.jp/eng/

I've tried Gaijinpot but they only seem to offer 1 year services only

I found some accommodations but I am not sure if the website/accommodations are legitimate, or how to determine whether it is safe. Are these websites safe? And what are other legit websites.