Is it permissible for the legal guardian or blood relative of an adult orphan to give her in marriage without her acceptance?
If the case is as you have mentioned, the Waliy (a legally accountable person acting for a woman regarding marriage) is not permitted to give her in marriage without her consent, as it is authentically reported that the Prophet (peace be upon him) said,
“A virgin should not be given in marriage until her permission has been sought.” They asked, “O Messenger of Allah! How does she give her permission?” He said, “By keeping silent.”
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.