Here's how you would say "My name is" in those languages:
Shona:
* Ndinonzi... (Formal)
* Ndini... (Informal)
Ndebele:
* Ngingu... (Formal)
* Mina ngingu... (Informal)
You can then follow that with your name. For example:
* Ndinonzi John. (My name is John, in Shona, formal)
* Ndini Sarah. (My name is Sarah, in Shona, informal)
* Ngingu Mary. (My name is Mary, in Ndebele, formal)
* Mina ngingu David. (My name is David, in Ndebele, informal)
It's always best to ask a local what the correct way to say it is, as there might be regional variations or a preferred way to say it in a specific context.