Actually, you all are wrong. What he really says is "Erin, will you marry me because we are meant to be together." He just says it really fast so it sounds like a short word such as "what" or "nuts" or "meow".
"You know, a little orphan girl once told me that the sun would come out tomorrow. Her adopted father was a powerful billionaire, so I supressed the urge to laugh in her face. But now, by gum, I think she might have been on to something!"
--Reefer Madness