Looking for Help - Johannesburg: Where to say and what to expect?

Hello guys, I'm travelling to JHB tomorrow. I wanted to book a room in a Hotel but someone told me that the hotel was located in a unsafe area. I've seen some hotels in Sandton but they are quite expensive and we're on a very tight budget. Are there any other safe areas besides Sandton? Any hotel suggestions?

Also, I'm Mozambican. Should I fear Xenophobia? and what to expect of Johannesburg in a general view?

Thank you

Edit: Sorry, title should have said: "Where to stay" instead of "Where to say".