Although Kaṁsa was a sinful demon, he believed that Vasudeva would never deviate from his word. The character of a pure devotee like Vasudeva is such that even so great a demon as Kaṁsa firmly believed in his words and was satisfied. Yasyāsti bhaktir bhagavaty akiñcanā sarvair guṇais tatra samāsate surāḥ (Bhāg. 5.18.12). All good attributes are present in a devotee, so much so that even Kaṁsa believed in Vasudeva’s words without a doubt.