Yes. When writing unsafe, you have to assume you can never trust anything coming from safe rust. But you are also provided far fewer rakes to step on when writing unsafe, and you (ideally) are writing far fewer lines of unsafe code in a Rust project than you would for equivalent C.

Rust is written in Rust, and we still want to be able to e.g. call C code from Rust. (It used to be the case that external C code was not always marked unsafe, but this was fixed recently).