To get the string value of div use:
string(/div)
This is the concatenation of all text nodes that are descendents of the (top) div element.
To select all text node descendents of div use:
/div//text()
To get only the text nodes that are direct children of div use:
/div/text()
Finally, get the first (and hopefully only) non-whitespace-only text node child of div:
/div/text()[normalize-space()][1]