For modern C++, use cppyy: http://cppyy.readthedocs.io/en/latest/
It's based on Cling, the C++ interpreter for Clang/LLVM. Bindings are at run-time and no additional intermediate language is necessary. Thanks to Clang, it supports C++17.
Specific to the original question of using Qt: several recent updates were done explicitly to support bindings generation for all of KDE.
For speed: cppyy is natively supported by PyPy.
Note: I'm the main author of cppyy.
