The ruling on swearing an oath of divorce to deny something, when it is later proven to be true

Question:
A man divorced his wife with a revocable divorce, then took her back into his marriage, and she became pregnant by him. She then traveled to her family’s home to give birth, while he traveled to another region. A letter from his wife reached him requesting supplies for the delivery. A colleague of his brought this letter and said, “This letter is from your wife.” He denied that and swore an oath of divorce that the letter was not from his wife. After it became clear that it was from his wife, he returned to his wife. The marriage officer of the village told him that the divorce had taken place because he said, “I divorce her.” Since the waiting period had passed, a new marriage contract was drawn up for them, and it was counted as a second divorce. Then Allah the Exalted willed that he divorce her again, so it was counted as a third divorce. The question is: Does the second divorce, which was sworn in regarding the letter, take effect? And is the wife considered divorced three times, such that she cannot be taken back? Please inform us; may Allah reward you.

Answer:
In the name of Allah, the Most Gracious, the Most Merciful. Praise be to Allah, and may Allah send blessings and peace upon the Messenger of Allah, and upon his family and his Companions, and upon those who follow his guidance. As for what follows: There is a distinction regarding the second divorce in which the husband swore that the letter was not from his wife. If he swore this while believing that what he said was true, and he believed that the writing was not her writing, or not the writing of the person who claimed in the letter to have written it on her behalf—meaning he believed that this letter was not valid and not from his wife, either because he knows her handwriting and this is not her handwriting, or because he knows the handwriting of the writer who claimed to be him and this is not his handwriting—the point is, if he believed that the handwriting was not from his wife and that it was written on her behalf, and that was his belief, then the divorce does not take effect, and she still has one divorce remaining. Yes. May Allah bless you.