[Machine] The Prophet ﷺ proposed to Zainab, who was the daughter of his cousin, with the intention of marrying her to Zaid. However, she misunderstood and thought that he wanted to marry her himself. When she found out that he actually intended to marry her to Zaid, she refused. Then Allah revealed the verse: "It is not for a believing man or a believing woman, when Allah and His Messenger have decided a matter, that they should [thereafter] have any choice about their affair." So she accepted and agreed.  

خَطَبَ النَّبِيُّ ﷺ زَيْنَبَ وَهِيَ بِنْتُ عَمَّتِهِ وَهُوَ يُرِيدُهَا لِزَيْدٍ فَظَنَّتْ أَنَّهُ يُرِيدُهَا لِنَفْسِهِ فَلَمَّا عَلِمَتْ أَنَّهُ يُرِيدُهَا لِزَيْدٍ أَبَتْ فَأَنْزَلَ اللهُ {وَمَا كَانَ لِمُؤْمِنٍ وَلَا مُؤْمِنَةٍ إِذَا قَضَى اللهُ وَرَسُولُهُ أَمْرًا أَنْ يَكُونَ لَهُمُ الْخِيَرَةُ مِنْ أَمْرِهُمْ} فَرَضِيَتْ وَسَلَّمَتْ