Question: If one, though believing that music is haram, says, "I like this song very much, and the singer who is singing it is very beautiful," does he fall into disbelief?
These statements do not cause disbelief. What causes disbelief is to deem a haram thing to be halal or to describe something haram as good. If a female disbeliever is beautiful, it is not disbelief to describe her as beautiful. Saying, "Such and such is haram, but I take delight in doing it," is not disbelief. So is the case with listening to songs by believing that listening to them is a sin. Our nafses get pleasure from them. Sins may please the nafs.
It causes disbelief to regard a haram thing as halal, to approve it, or to say that it is good and nice. It is not disbelief to describe a beautiful person as beautiful or to describe a female singer or her voice as lovely. It does not cause disbelief to say, "I take delight in committing fornication." However, it is disbelief to approve it, to deny that it is a sin, or to say that it is halal and good. It is not disbelief to commit it by knowing that it is haram or to say, "I get a lot of pleasure from it." The subtlety here is that considering a haram thing to be good is different from getting pleasure from it.
If a thief breaks loose from police officers after playing some tricks and if we like and admire his tricks and say "Bravo!" to the thief, it is not disbelief because we do not consider the crime of stealing to be good, but we have liked his tricks. Similarly, we may like the voice or beauty of a singer. It is not disbelief to say that her voice is lovely.
However, we should act cautiously because Islamic scholars state, "Harams are the sustenance of the nafs." The nafs-i ammara (the nafs that commands evil) is a disbeliever and idiot. Its each and every desire is to its own disadvantage and results in harm to it. Therefore, we should not fulfill its whims and thus should not give sustenance to it; that is, we should not commit sins. If the nafs and Satan gain complete control over us, we cannot restrain ourselves from committing sins even if we do not want to commit them. In such a case, we sin deliberately. The similitude of it is a driver who cannot control a car with failed brakes. It is unknown where he will stop and crash into. Today, most people are in this state.
Question: It is claimed, "If one says 'She is beautiful' about a beautiful woman, one becomes a disbeliever." Why does it cause disbelief to describe a beautiful woman as beautiful?
It is not disbelief to describe a beautiful woman as beautiful. What is disbelief is to consider a haram thing to be halal or to say "good" about something haram. However, if a woman is rather indecently dressed and if a person says "good" about her dressing style, the relevant person falls into disbelief.