She was in love with him.
The princess Ariadne helped Theseus.
Daedalus
King Minos's daughter, Princess Ariadne of Crete.
ariadne
Ariadne gave Theseus a ball of golden cord to navigate his way through the labyrinth. I also believe that she gave him a sword to kill the minotaur.
A string that led through the Labyrinth.
To help Ariande's lover Theseus.
Ariadne gave him a ball of thread to help him escape from the Labyrinth because Ariadne loved him and didn't want be eaten by the Minotaur.
For love of Theseus.
It was Ariadne, daughter of Minos, who wanted to marry Theseus. But there were other women in Theseus' life, both before and after Ariadne.
Theseus abandoned Ariadne because he forgot to take her with him when he left the island of Crete after defeating the Minotaur.
Theseus had her help in overcoming the Minotaur and saving the would-be sacrificial victims.