Hazrat Qasim bin Muhammad used to say in the explanation of this verse: «﴿ولَاجُنَاحَعَلَيْكُمْفِيمَاعَرَّضْتُمْبِهِمِنْخِطْبَةِالنِّسَاءِ،أَوْأَكْنَنْتُمْفِيأَنْفُسِكُمْ،عَلِمَاللّٰهُأَنَّكُمْسَتَذْكُرُونَهُنَّ،وَلَكِنْلَاتُوَاعِدُوهُنَّسِرًّا،إِلَّاأَنْتَقُولُواقَوْلًامَعْرُوفًا﴾ [البقرة: 235]» That is, there is no sin upon you to make an indirect proposal to a woman when she is in her waiting period (‘iddah). Indirect proposal means that a man sends word to a woman: "I like you," or "I desire you," or "May Allah grant you goodness and sustenance," or says something similar.
Hadith Referenceموطا امام مالك رواية يحييٰ / كتاب النكاح / 1076