Use another program like Photoshop if you have it or even something cheaper like Google Slides (then, just screenshot the text on the picture or use the 'Snip' programs). Even when you use the skew option, your letters would become distorted. On the other hand, MSPaint is not truly meant to allow rotation of text. See which amounts fit best for you (Note: If you want your text to curve, you would have to adjust both the vertical and horizontal pixels/percentages of the skew.) That is the 'skew' option where you can make your text turn in a way. If you look at the bottom section of the 'resize' area, you will see something with two parallelograms.Use the selection tool and 'lasso' the text.
You probably should know where the 'selection' tool is, so crank out that bad boy and test it out:
No, I am not talking about the 'rotate' selection, I am talking about how you can use the 'resize' selection. MSPaint has somewhat of a way of rotating text.