It was narrated that Abu Hurairah said:"The Messenger of Allah said: 'An orphan girl should be consulted with regard to marriage, and if she remains silent, that is her permission. If she refuses then she is not to be forced.'"
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا يَحْيَى، قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ عَمْرٍو، قَالَ حَدَّثَنَا أَبُو سَلَمَةَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " تُسْتَأْمَرُ الْيَتِيمَةُ فِي نَفْسِهَا فَإِنْ سَكَتَتْ فَهُوَ إِذْنُهَا وَإِنْ أَبَتْ فَلاَ جَوَازَ عَلَيْهَا " .
Nesai
The Book of Marriage • Hadith 3270