I'm guessing you are searching post comments 🙂 It's only possible to change by modifiing the source code, but you only need to edit 1 line.
If you have ftp access, then open up this file: wp-content/plugins/ajax-search-pro/includes/search_comments.class.php and go to line 70, you should see this:
$commentsresults[$k]->title = substr($commentsresults[$k]->content, 0, 15)."...";
If you want to change it to 20 characters, then replace that line with this:
$commentsresults[$k]->title = substr($commentsresults[$k]->content, 0, 20)."...";
Let me know if it helped or you need any assistance with this!Best,
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