Surah Al-Baqarah, ayah 235

وَلَا جُنَاحَ عَلَيۡكُمۡ فِيمَا عَرَّضۡتُم بِهِۦ مِنۡ خِطۡبَةِ ٱلنِّسَآءِ أَوۡ أَكۡنَنتُمۡ فِيٓ أَنفُسِكُمۡۚ عَلِمَ ٱللَّهُ أَنَّكُمۡ سَتَذۡكُرُونَهُنَّ وَلَٰكِن لَّا تُوَاعِدُوهُنَّ سِرًّا إِلَّآ أَن تَقُولُواْ قَوۡلٗا مَّعۡرُوفٗاۚ وَلَا تَعۡزِمُواْ عُقۡدَةَ ٱلنِّكَاحِ حَتَّىٰ يَبۡلُغَ ٱلۡكِتَٰبُ أَجَلَهُۥۚ وَٱعۡلَمُوٓاْ أَنَّ ٱللَّهَ يَعۡلَمُ مَا فِيٓ أَنفُسِكُمۡ فَٱحۡذَرُوهُۚ وَٱعۡلَمُوٓاْ أَنَّ ٱللَّهَ غَفُورٌ حَلِيمٞ ٢٣٥

Walā junāha 'alaykum fīmā 'arradtum bihī min khitbatin-nisā'i aw aknantum fī anfusikum 'alimallāhu annakum satadhkurūnahunna walākil lā tuwā'idūhunna sirran illā an taqūlū qawlam ma'rūfan walā ta'zimū 'uqdatan-nikāhi hattā yablughal-kitābu ajalahū wa'lamū annallāha ya'lamu mā fī anfusikum fahdharūhu wa'lamū annallāha ghafūrun halīm

There is no blame upon you for that to which you [indirectly] allude concerning a proposal to women or for what you conceal within yourselves. Allāh knows that you will have them in mind. But do not promise them secretly except for saying a proper saying. And do not determine to undertake a marriage contract until the decreed period⁹³ reaches its end. And know that Allāh knows what is within yourselves, so beware of Him. And know that Allāh is Forgiving and Forbearing.