She said, The Philistines are on you, Samson. He awoke out of his sleep, and said, I will go out as at other times, and shake myself free. But he didn't know that Yahweh had departed from him.
The fact that Samson told Delilah to do something to his hair (Judges 16:13) suggests that he was giving her a clue to his strength. She did not pick this up but kept hounding him for his secret. Finally he gave in (Judges 16:17; cf. Judges 14:17).