Must I tell the girl of my desire to marry her and hear her response, or should I leave it to fate after her father refused and said that she wishes to marry her cousin and complete her studies abroad?

If the woman mentioned is engaged to her cousin, then it is not permissible to propose to her. However, if she is not engaged, then it is permissible to speak with her without being in seclusion (khalwa) and within the bounds of Islamic law. It is forbidden for a man to propose over the proposal of his brother if the latter has explicitly accepted, unless the first suitor relinquishes his claim or gives permission. The prohibition is contingent upon the woman or her guardian having given an answer.