What is the legal ruling when a wife hears from her husband something resembling, "You are within a 'bow's length or nearer' of being divorced," and she fears asking him about his intention lest he become angry, so is she sinful if she remains silent?

A woman is not required to ask her husband about his intention if she suspects that a divorce has occurred, because the fundamental principle is the continuation of the marriage, and divorce does not take effect with doubt. The statement mentioned in the question does not constitute a divorce. The wife is advised to live with her husband righteously and to abandon doubts and obsessive thoughts.