The formal proof doesn’t exist yet but the language was designed from the ground up with memory safety as a key principle.

I should note, Rust is not the only safe language. Python is safe, as are most modern languages with garbage collection. Most code can afford a garbage collector and should probably use one. My day job is real-time network + web services with Elixir/Erlang, and it works great. Rust gets brought up in contrast to Zig because it brings the benefits of those higher-level languages down to the metal.