1. Cena beats Rock, then they shake hands and show each other a sign of respect. The most boring and predictable scenario. 2. Cena beats Rock, and then the next night, he starts to brag about beating The Rock in a very heelish way. The fans already hate him, so it's not like he has to do something controversial (like Austin and Hogan) to officially turn him heel. Maybe he just starts responding to the fans who hate him and turns his back on the ones who do still cheer him. Kinda soft, but still possible. 3. Cena beats The Rock (or Rock beats Cena), but the next night, Rock offers a handshake of respect. But after Cena shakes his hand (or after he refuses), Cena attacks Rock and absolutely destroys him, thus officially turning him heel. 4. Same thing as above, except it happens after the match at WM instead of the next night on Raw. This might be smarter since it would be a huge Wrestlemania moment and one that takes advantage of the Rock's Miami homecrowd.