Carlisle believed that she should have a classical education. The first languages she learned under his tutelage were Greek and Latin, and she read Homer and Virgil and Ovid and Herodotus and all those other men who mattered so much to the Great Western World. She didn't really enjoy it and they moved quickly on to other things, but a few years later when she was reading Romantic poetry he backtracked and gave her a volume of Plutarch. She was puzzled and a little annoyed, but she read it, and to the last moment of her life she didn't forget it.
There was a story inside about a Spartan youth who stole a fox. Some of his superiors met up with him on the road and he was terrified that they would find out what he had done, so he hid the fox beneath his cloak and strode up to greet them. When the fox began to disembowel him right there, in the middle of the road under his cloak, he didn't make a sound. He was a Spartan, after all. He could have flung the fox away and perhaps kept his intestines, but the shame of being found out was by far the more frightening prospect.
If Renesmee had been a little older she would have known that you can't do that forever—bite your lip and hope no one notices that something is killing you. Eventually you scream or fall over or bleed out on the ground, and everyone knows. Everyone knows and it's already over.
And that's exactly what happened.