It is narrated from Hazrat Abu Hurairah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Permission should be sought from a virgin girl for marriage, and consultation should be done with a previously married woman." Someone asked: "O Messenger of Allah! A virgin girl feels shy (so how should her permission be obtained?)" The Prophet (peace and blessings be upon him) said: "Her silence is her consent."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 7131