The Win32 API has the edit control and the richedit control. You can't highlight just certain words with a normal edit control, but you can with a richedit control (using RTF).
{\rtf1\ansi\deff0
{\colortbl;\red0\green0\blue0;\red255\green0\blue0;}
This line is the default color\line
\cf2
This line is red\line
\cf1
This line is the default color
}
There is a TextBox in the .Net Forms library which can be used via C++/CLI, but that's another story. I haven't used it, but there's a RichTextBox which allows you to control the text color.