Suggestion - Library or Reference for C++ Method Calls from C#

I want to ask about any available library that can ease dealing with C++ from C#. In short, I want to call C/C++ methods from C# without using DllImport. So far, I have tried with reflection, it sounds okay. but I am going to have intensive calls to C++ with different parameters' types and returned data. So, I thought if there is a library OR a good reference with details (e.g., books) regarding this matter would be better. I found so far only Fasterflect library, but it does not seem easy to use for C++ calls when it comes to passing parameters such as string.

Thank you