formatting problems

Every time I post a story here I have to go though and fix the line spacing. I will get sentences like this:

This sentence must be to long for the website because
it does this.
and the the next sentence is below like this.

I write in libre office and then copy and paste. Also, while I'm asking, how do I center something like the inscription in The Lynching Tree. It was centered in my draft but moved to the margin when copied.