How can i turn him down?

Some of the Ugliness can be fixed. LIke if he is slim, you can later make him fat or if he is obese make him do exercise and buildup his body. Some of the men keep big dark gles all the time (even at night!!). Sometimes that's boring and can be removed. Just think all the aspects and it's a matter of your future and you are the ones to decide. So pray Isthikhara and supplicate a lot. Only finally tell your parents the matter what comes to your heart.