Hi Karine,
you might try this:
Select the text.
Start a Makro that:
1. puts the text in a variable
2. collapses the cursor to the left.
3. Get Selection.Information(7) ' eg. into pos1
' wdHorizontalPositionRelativeToTextBoundary = 7 !!!
4. search for the text
5. Collapse the cursor to the right.
6. Get Selection.Information(7) ' eg. into pos2
pos2 - pos1 is the width of the selection,
if the selection restes on one (!) line.
If the selection spans over more than one line,
it's becoming still more complicated.
pos2 - pos1 is the textwidth in Twips
20 Twip = 1 Point, 72 Point = 1 Inch
There are other methods, that could vary in detail,
though, it's never quite simple and straightforward.
Greetings from Bavaria, Germany,
Helmut Weber