When Abby (and then Hale) first accuse Tituba of witchcraft, she totally denies having anything to do with it. She is "shocked and angry" at Abby for saying that she forced them to do things. And she tells Hale that she "don't truck" with the devil. So she is denying that she has anything to do with witchcraft.
But just a little later (in the same conversation) she seems to be admitting that she has seen the devil. Hale asks her if the devil comes to her with anyone else. At that point, she says "was woman." This implies that the devil has come to her and has come along with some other woman to see Tituba. Then, when Hale says she has confessed to witchcraft, Tituba does not protest.
So at first she is denying any connection, but then she seems to be admitting to it (or at least she no longer denies it).