Does a divorce take effect when a man says to his wife: "If you go to your uncle's house, you are forbidden to me," believing that this means divorce, but his intention was only to threaten and prevent, and then the wife went, not knowing the meaning of that statement?

What you uttered is a comment to prohibit your wife from going to her uncle's house. The preponderant opinion regarding it is that it depends on the husband's intention. You mentioned that you intended to threaten and prevent her. If the conditioned event occurs, then only an expiation for an oath becomes binding upon you. One should be cautious about being lenient with words of divorce and prohibition, and problems should be solved through understanding and dialogue. It is not good to prevent a wife from going to her uncle's house except for a legitimate reason.