Yours faithfully,

"He's that rare combination of up-to-something and good-for-nothing." - The Simpsons

"There are many ways to fry an egg. There's more than one way to skin a cat. For the people who like their eggs with skinned cat, the possibilities are limitless." -Me (Wonder if it's funny though.)

"Snape from Harry Potter fits the bill pretty well. Throughout books 1-6 and most of book 7, seemingly everybody except Dumbledore and Voldemort thinks that Snape is a spy for the other side. He does a damn good job of keeping it that way, especially after the ending of book 6.

* Its hard to say without giving spoilers, but in the end it turns out that despite his glaring obvious other character faults, there is hardly a more faithful person imaginable than Snape, both in love and friendship. Despite being rejected by Harry's mother Lily, he stays true to her until the very end and never seemed to have even looked at another woman (even if he himself made her snap and reject him by calling her a mudblood, something he never forgave himself for). He also stays faithful to unbelievable degrees to Dumbledore. "- TV Tropes, Chronic Backstabbing Disorder.

Not ever looking at another woman. Try imagining that. Seriously.