You are being tricked

When they arrived in Itrusia, Marlena couldn't hide her curiosity anymore. She asked Destrian, "Are demons tied to their mates forever without any way of breaking the bond?". Destrian halted in his steps and looked at her. 

It seemed like the young woman was truly curious about this, but he couldn't figure out why. Was she feeling pity for him because he had to endure the pain of wanting to be with someone and being compelled to get close to her but not being able to actually get together with her? 

To her question, he said, "There is one way." 

"Really?" her eyes brightened. 

He nodded. "There's a sword nicknamed The Immortal. It once belonged to my ancestor Alvarin. If you use it to stab me through my heart, my bond with you will immediately be broken." 

Marlena nearly believed his nonsense for a second. He made it sound so sophisticated.

She frowned at him in annoyance when she understood him. "You might as well say I should kill you."