the illusion, manifesting a few days after becoming engaged, that women you know other than your fiancée have become vastly more attractive than they were before your engagement, causing you to temporarily question your decision to propose.

Origin: The engagement is sealed with a diamond ring, and your female friends aren't actually any more attractive than they used to be; hence, the "diamond deception."
Guy 1: Hey, congratulations on your engagement last week!
Guy 2: Thanks, bro.
Guy 1: How does it feel?
Guy 2: Well, honestly, these last few days I've been noticing how hot all my female friends are. But now that I'm engaged to be married, I'll never be with any other naked woman again!
Guy 1: Oh man... you're totally suffering from the diamond deception!
by newfiance June 28, 2010
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