Is it permissible for the wife to ask for divorce if she dislikes her husband, even if the dislike is without reason, and would she be sinful if she asks for divorce for that?

If a woman dislikes her husband, and he is a righteous man, it is recommended for her to be patient and make supplication. However, if she fears that she will not be able to fulfill his rights, she may seek separation through divorce (talaq) or khul', in accordance with the Almighty's saying: (But if you fear that they will not uphold the limits of Allah, then there is no blame upon either of them concerning that by which she ransoms herself) [Quran 2:229]. The Prophet, peace and blessings be upon him, approved the request of the wife of Thabit ibn Qays for separation because she disliked him. There is no sin upon a woman for seeking divorce due to her dislike for her husband, but patience is better for her.