Is the last divorce counted as the third or the second, and what is the religious ruling on that, and how can the wife be convinced?

Doubt regarding divorce does not remove the certainty of the marital bond, because doubt does not override certainty. If the doubt concerns the number of divorces, then the lesser, certain number is upheld, and this is the view of the majority of scholars. If a woman claims a triple divorce, her claim is not accepted judicially except with the husband's acknowledgment or the testimony of two just witnesses. A wife who is doubtful can be convinced by the words of scholars. However, if she becomes certain that the third divorce has occurred, there is no way to convince her otherwise, and she is irrevocably divorced from you. In case of dispute, recourse should be made to the Sharia courts.