Praise be to Allaah.
It is not permissible for a woman to be made to marry someone she does not want. The Messenger of Allaah (peace and blessings of Allaah be upon him) said: A previously-married woman should not be married without being consulted, and a virgin should not be married without asking her permission. They said, O Messenger of Allaah, how is her permission given? He said, By her silence.(Reported by al-Bukhaari, 6455).
Aaishah reported that a girl came to her and said, My father married me to his brothers son in order to raise his social standing, and I did not want this marriage [I was forced into it]. Aaishah said, Sit here until the Prophet (peace and blessings of Allaah be upon him) comes. The Messenger of Allaah (peace and blessings of Allaah be upon him) came and she told him about the girl. The Prophet (peace and blessings of Allaah be upon him) sent for her father, then he gave the girl the choice of what to do. She said, O Messenger of Allaah, I have accepted what my father did, but I wanted to prove something to other women.(Reported by al-Nisaai, 3217).
So, both the guardian and the woman must agree to the marriage. With regard to your request for our advice regarding the problem mentioned in the question, so long as this marriage has taken place, it is better for the woman to try to keep it going as much as she can, and to try to accept this husband. She should seek reward through pleasing her parents and also try to reform her husband through a gentle approach and praying for guidance for him. And Allaah is the Source of Strength.