Slashes and broken links in newsletter

Hello, I have problems with the newsletter because after every apostrophe appears a slash and the links doesn’t work. In the preview of the newsletter works well, but the emails to the users appear like this:
“Si è concluso da pochi giorni il raduno annuale delle Lambda, che quest\’anno si è svolto all\’Isola d\’Elba. Guarda le prime foto e leggi il resoconto (vai)” (the link doesn’t works).
I tried to disabled all plugins to verify conflicts, to disabled magic quotes in functions.php and in the .htaccess file, following a guide found on Google and to change the Mail Type, but nothing worked. Could you help me please?. I use this plugin on other sites and I don’t have similar problems. Thank You