Cassian took an ample amount of his time to thoroughly think about it which was why he was confident enough to say it to her. He wanted to make her conscious of the fact that he wanted her, and also prove to the stubborn woman that he has no intention of marrying another - not in this life or the next to say the least.
As much as he planned to take this discussion very seriously in order to strengthen the length of their marriage, Cassian couldn't stop the tittering sound that left his lips after hearing her innocent reason for outrightly refusing to get in bed with him.
She was afraid he'd break her, and to be hundred percent honest considering that logic, he does have the evil intention of breaking her along with the bed, but certainly not in the beginning.
