There are two versions. One is that Apollo gave her the power because of her beauty. The other version is that Cassandra spent a night in Apollo's temple and snakes licked her ears clean which gave her the power of prophecy.
Cassandra
No; she used his love for her. Cassandra was loved by Apollo. She tricked Apollo into granting her the gift of prophecy - but refused to lie with him, and was cursed by the god for her prophecy to not be believed.
She was given the gift of prophecy by the god Apollo. she later betrayed him so he cursed this meant that no one believed her prophesy
Yes. Apollo loved Cassandra but Cassandra resented him. Apollo gave her the gift of prophecy but when she resented him Apollo cursed Cassandra so that no one would believe a word that she said.
Zeus did not give Cassandra her ability, this was the gift of Apollo (or she always had the ability and when she rejected Apollo he cursed her prophecy not to be believed).
Because Apollo loved Cassandra, he gave her the gift of prophecy. When she refused to return his love, he placed a curse on her so no one believed her prophecies.
Because of her beauty, but because she did not accept him as a lover he cursed this to say that no-one would belive her
That would be Cassandra.
Cassandra was the daughter of King Priam and Queen Hecuba in Homer's Iliad. Apollo granted Cassandra the gift of prophecy, but when Cassandra rejected Apollo's advances, she was cursed to tell the truth about the future, but never to be believed.
Cassandra
He desired her, and attempted to woo her, giving her the gift of prophecy. However, she rejected him. Therefore, he cursed her by allowing no one to believe her prophecies.
You are probably thinking of Cassandra, the daughter of Priam. She was given the gift of prophecy by Apollo, but was cursed to have nobody believe her.