Python is a high-level interpreted language, and C/C++ are low-level (even compared to other) compiled languages. While you might be able to optimize your Python code to run faster than it does now, it's never going to match the performance of C/C++, nor is it intended to.
Go will be a significant speedup over Python, but likely won't quite match the speed of C/C++ for most tasks. Then again, the ease of development in Go will likely be noticeably better than in C or C++. Rust could potentially match the speed of C++, but it's a much more complex language than Go, so it will take some time to master. (Personally, having spent a large amount of time programming in Rust, I find myself more productive than in Go due to the powerful abstractions present in the former and lacking in the latter, but conventional wisdom is that this won't be the case for most people, and it certainly won't be when you're first learning Rust).
EDIT: Anecdotally I've heard that D is a nice language, but I have no experience with it, so I can't comment on how productive it is or how fast D code will run.