He never knew his feelings for her,
In other words,
He had speculated on his own thoughts, but never recognized them clearly.
He,
It's the excellent Tom Marvolo Riddle,
It's the cold Lord Voldemort,
He is a descendant of the Gaunt family, a branch of Slytherin.
She,
She is an amnesiac girl without a last name.
Or, the noble Sydelle Slytherin.
Based on blood ties,
For the sake of love,
To imprison two souls who know each other and stay together.