How to align the text in textbox, seems different character has different width
===

For multiline TextBox in wpf, i find the length of the chars of the text is not always equal. 
For instance, if i put kkk in the first line, "f f" in the 2nd line, they wont align...since f and space take smaller size.

How to stop that and make every char has the same size??

So that my strings can be align?