At the climax of the movie, during the ceremony to contain 'The Curse', Rose is asked to drink from a cup. She picks it up from it's place next to the ceremonial candles and does so, when she does, her body convulses and she drops the cup. It rolls across the floor, but moments later she is seen laying on the floor next to the ceremonial candles, with the cup sitting neatly in it's place, upright and next to the candles.
The grudge curse was created when Takeo murdered both his wife, Kayako, and son, Toshio. Naoko tries to end the curse by getting Rose to drink Kayako's blood during the ceremony she held in the apartment where the curse was reborn. Drinking Kayako's blood would unlikely stop Toshio's ghost, meaning only Kayako would be stopped. This would mean that the curse would not have been ended by Naoko's ceremony.