It will require some hard coding, because that text actually a iframe that addressed to facebook (it is an official facebook plugin) there fore, you need to increase the width size of that iframe little bit.
Open this page:
ROOT/templates/<yourjoomlatemplatefolder>/html/com_virtuemart/html/productdetails/default.php
and look for this HTML line:
<i-frame src="//www.facebook.com/plugins/like.php?href=<?php echo currentPageURL();?>&send=false&layout=standard&width=40&show_faces=false&action=like&colorscheme=light&font&height=35&appId=115329165206253" scrolling="no" frameborder="0" style="border:none; overflow:hidden; max-width:100%;height:29px;" allowTransparency="true"></iframe>
It must be around 695th line.
And change it with this:
<i-frame src="//www.facebook.com/plugins/like.php?href=<?php echo currentPageURL();?>&send=false&layout=standard&width=140&show_faces=false&action=like&colorscheme=light&font&height=35&appId=115329165206253" scrolling="no" frameborder="0" style="border:none; overflow:hidden; max-width:100%;height:29px;" allowTransparency="true"></iframe>
If it doesn't enough, or it becomes too large, then alter it by yourself. Look at the HTML line closely, somewhere in the code, there is this expression: &width=140
(it is in pixel), change it to whatever you want.
Regards.
Forum support.