By the standard of your “first,” no language is a memory safe language. They all must rely on unsafety in the implementation of their runtimes in the same sense that Rust builds safe abstractions on top of unsafe code, and many even offer FFI, which is conceptually similar to calling an unsafe function.
Most memory safe languages lack enough power to implement their own runtime systems (except in an extremely inefficient way), because so many languages ultimately rely on an implementation in another unsafe language that has access to machine capabilities. Implementing the runtime system in the language itself is a black art that requires an unsafe dialect or extension. E.g. all the Java-in-Java VMs sneak dialect features in through intrinsic classes like "Pointer" and such that are recognized by their own extended compilers.
