Who is who

Jaime Lannister had only ever truly loved one girl and it was not his sister. It was the mother of his sons Daemon Lannister the heir to Casterly Rock and Lyros Lannister and his daughter Visenya Lannister.

Her name is Rhaenyra Targaryen.
The Suneshine of the Realm.
The beloved sister to Rhaegar Targaryen, daughter of the man he had killed Aerys Targaryen.

But no longer, their love once sung by bards now was dried and gone vanished when he killed her father who might have been mad, but he was her father and her brother died at the hands of Robert Baratheon