Rust is one of the safer languages, but saying that it is "the safest language" is just a baseless exaggeration.

Decades before Rust and long before the simplified language that was C, there were safe programming languages, where all invalid operations, numeric overflows or out-of-bounds accesses generated exceptions and where use-after-free was impossible, because either garbage collectors or reference counts were used.

Rust is much safer than C compiled with its bad default compilation options, but it did not bring much in comparison with other languages.

Even in C++, with appropriate rules, restrictions and discipline you can write programs that are guaranteed to be at least as safe as any Rust program, but unfortunately very few use C++ in this way, i.e. by strictly avoiding the features that are obsolete or unsafe.