Manipulating Text with tkinter

My plan was to show strings and then highlist specific letters, depending on the index of the letter. To give you an idea, this is extly how it should look in the end: click me

I wanted to use tkinter and it's canvas, but now I know, that it can't highlight specific letters in a string.

Do you have an idea, how I could do that? I am also open to using something other than tkinter.

Thanks