Does a triple divorce take place if the husband prevents his wife from going out by saying, "By triple divorce, you are not leaving," with the intention of preventing her from going out for a specific occasion, and the wife later went out for other matters not agreed upon, knowing that he has not yet consummated the marriage with her?

If you have validly married her according to Sharia and swore by triple divorce intending to prevent her from going out to buy a specific item, and she did not go out for that purpose, then there is no breach of the oath if she goes out for another matter, as an oath is based on the intention of the swearer. We warn against swearing by divorce in the future. However, if the Sharia marriage contract has not been concluded, then she is a non-mahram woman to you, and divorce does not apply to her, and it is forbidden for you to be alone with her.