Sahih Bukhari Volume 7, Book 67, Hadith 5126

وَقَالَ لِي طَلْقٌ حَدَّثَنَا زَائِدَةُ، عَنْ مَنْصُورٍ، عَنْ مُجَاهِدٍ، عَنِ ابْنِ عَبَّاسٍ، ‏{‏فِيمَا عَرَّضْتُمْ‏}‏ يَقُولُ إِنِّي أُرِيدُ التَّزْوِيجَ، وَلَوَدِدْتُ أَنَّهُ تَيَسَّرَ لِي امْرَأَةٌ صَالِحَةٌ‏.‏ وَقَالَ الْقَاسِمُ يَقُولُ إِنَّكِ عَلَىَّ كَرِيمَةٌ، وَإِنِّي فِيكِ لَرَاغِبٌ، وَإِنَّ اللَّهَ لَسَائِقٌ إِلَيْكِ خَيْرًا‏.‏ أَوْ نَحْوَ هَذَا‏.‏ وَقَالَ عَطَاءٌ يُعَرِّضُ وَلاَ يَبُوحُ يَقُولُ إِنَّ لِي حَاجَةً وَأَبْشِرِي، وَأَنْتِ بِحَمْدِ اللَّهِ نَافِقَةٌ‏.‏ وَتَقُولُ هِيَ قَدْ أَسْمَعُ مَا تَقُولُ‏.‏ وَلاَ تَعِدُ شَيْئًا وَلاَ يُوَاعِدُ وَلِيُّهَا بِغَيْرِ عِلْمِهَا، وَإِنْ وَاعَدَتْ رَجُلاً فِي عِدَّتِهَا ثُمَّ نَكَحَهَا بَعْدُ لَمْ يُفَرَّقْ بَيْنَهُمَا‏.‏ وَقَالَ الْحَسَنُ ‏{‏لاَ تُوَاعِدُوهُنَّ سِرًّا‏}‏ الزِّنَا‏.‏ وَيُذْكَرُ عَنِ ابْنِ عَبَّاسٍ ‏{‏الْكِتَابُ أَجَلَهُ‏}‏ تَنْقَضِي الْعِدَّةُ‏.‏

Ibn 'Abbas said, "Hint your intention of marrying' is made by saying (to the widow) for example: "I want to marry, and I wish that Allah will make a righteous lady available for me.' " Al-Qasim said: One may say to the widow: 'I hold all respect for you, and I am interested in you; Allah will bring you much good, or something similar 'Ata said: One should hint his intention, and should not declare it openly. One may say: 'I have some need. Have good tidings. Praise be to Allah; you are fit to remarry.' She (the widow) may say in reply: I am listening to what you say,' but she should not make a promise. Her guardian should not make a promise (to somebody to get her married to him) without her knowledge. But if, while still in the Iddat period, she makes a promise to marry somebody, and he ultimately marries her, they are not to be separated by divorce (i.e., the marriage is valid).