how do i reverse italic text

When you have selected the object using picker tool (F1), then the standard toolbar has an icon for horizontal flipping.

If I understand the question correctly, one solution would be the following:

1 - create your text using the text tool (F8). Use a normal font, not italics.
2 - activate the select tool (F1)
3 - click on your text in order to select it. You will see 8 arrows around the bounding box of your text, for scaling it. Such arrows are oriented in the radial direction (i.e. they point towards the center of the object)
4 - click again over your text. The arrows will now be different: the one at the top/bottom, for example, will be horizontal rather than vertical
5 - click and drag horizontally the top arrow. This will slant your text.

For more information, this is covered under point:
"Moving, scaling, rotating"
of the inkscape basic tutorial (Help -> Tutorials -> Inkscape: Basic)