Someone has told me that I look more beautiful in the Hijāb. Does this not defeat the purpose of wearing it?
The purpose of wearing the Hijāb is not to look ugly. Its purpose is to look decent. If a lady looks more graceful and decent in the Hijāb, then looking graceful and decent is no sin. Muslim men, on the other hand, are directed not to stare at women. So even if a lady is wearing the Hijāb and as a result looking graceful, Muslim men must guard their gazes and refrain from staring at her.
In other words, if a lady is wearing the Hijāb, it does not mean that Muslim men can freely gaze at her. Rather they must look at her, if they have to, the way they would like others to look at their own sisters and mothers.