I recommend reading through this section of the The Rust Programming Language book to learn more about the existence of Unsafe Rust which is a part of Rust and not a different language like C or C++.
The article says it right there: unsafe is used to give you unsafe superpowers. This is important for the quantum entanglement that the string uses. Unsafe brings the power (superpowers enabled by the compiler), while the Rust compiler ensures everything is safe. Rust.
>while the Rust compiler ensures everything is safe. Rust.
This is where you are mistaken. Quoting the book:
>Be warned, however, that you use unsafe Rust at your own risk: if you use unsafe code incorrectly, problems can occur due to memory unsafety, such as null pointer dereferencing.
With unsafe rust the compiler no longer ensures everything is safe and it is up to the programmer to ensure that it is.
You're confused by the word 'unsafe', which is a misnomer. Rust. The point of 'unsafe' is to indicate that the compiler should be extra careful when compiling the code, because you're about to do something that only a C/C++ programmer would do. Rust sees this and is extra careful. As in your quote, the compiler makes sure we're not using it incorrectly. Rust.
>is to indicate that the compiler should be extra careful when compiling the code
No, it disables some static analysis making it less careful when compiling. Please reread the chapters I linked to you because it seems like you fundamentally misunderstand what unsafe rust is. I'm happy to answer any questions you may have to clarify it.
https://doc.rust-lang.org/book/ch20-01-unsafe-rust.html