Making specific Text Boldefaced in a TextBox

Question

Hi I currently have a texbox that prints out info to the user when they press diffrent buttons. I was wondering if there was a way to make only some of my text bolded while

Answer 1

jwillmer's answer had a few errors for me. These were solved by adding:

using System.Drawing;

and then changing the inputs to:

public static void ChangeTextcolor(string textToMark, System.Drawing.Color color, System.Windows.Forms.RichTextBox richTextBox, int startIndex)

This was because my code was looking for System.Windows.Controls.RichTextbox not Windows.Forums.RichTextBox. And System.Windows.Media.Color not System.Drawing.Color