Assalamu Alaikum, Respected Sister
South Africa is one of the most beautiful places ever created by Allah (SWT). Yes, we do have crime as is the case with most countries and the times we live in but if we put our trust in Allah (SWT) and his Rasool Muhammad Mustapha (SAW) no harm will ever come to you no matter where you find yourself. We should also be very careful of how the media portrais our country abroad.
Personally I am a European descendant Muslim man married to an Indian Muslimah, so staying in South Africa (having a racially hostile past) should be more of a problem to me than to you being an African person (I do not like the term 'black') in an African country. I've been staying in this country for 35 years by the grace of Allah (SWT) and have never experienced racial intollerance personally.
There are many African Muslim Sisters both locally as well as from countries like Somalia, Malawi, Nigeria etc. living in South Africa.
Also the Muslim community of South Africa is 'tight' we all accept each other as Allah (SWT) intended as Islam does not see race but Eemaan is what is important. You will find us all praying together in the same Masajied (Malaysian, Indian, African and European men.)
The predominant Mazhaabs (Schools of Thought) we follow is Hanafee and Shafee (in a lesser degree some adherents follow Hambali.)
I hope that above info will help you to make a decision. Always ask Allah (SWT) to help you choose/guide you and ask for a ayat (sign) from him.
Assalamu Alaikum Warahmatulahee wa Baraakatu.
Bro' Muhammad Riyaaz
"You are the best of peoples ever raised up for mankind; you enjoin what is right and forbid evil and you believe in Allah" - Surah Ali Imran 3:110.