How we cite our quotes:
"So," said Tuck to himself. "Two years. She's been gone two years." He stood up and looked around, embarrassed, trying to clear the lump from his throat. But there was no one to see him. […] Tuck wiped his eyes hastily. Then he straightened his jacket again and drew up his hand in a brief salute. "Good girl," he said aloud. (Epilogue.23)
Now that's love. If Winnie had drunk from the spring, she would have been there with the Tucks forever. But Tuck loves her and he wants what's best for her. And according to him, what's best for her is mortality.