The Prophet (peace and blessings be upon him) said: "A previously married woman is not to be married until she is consulted, and a virgin is not to be married until her permission is sought." The Companions (may Allah be pleased with them) asked: How will her permission be given, O Prophet of Allah? He (peace and blessings be upon him) said: "Silence is her permission."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13699