The Primordial Beast of Pride looked at the contract and liked that it mostly favored itself than the god that offered it. The only thing that the Primordial Beast of Pride needs to take note of is the fact that he must not become aggressive to Asgard. The Primordial Beast of Pride does not care for that because it believes that even Asgard will bow down to it once it becomes the Beast of Ogdoad.
The fact that the Aesir Gods would promise the Primordial Beast of Pride with the Infinity Core is something that the latter did not expect. This contract basically solidified the Primordial Beast of Pride becoming the Beast of Ogdoad. Still, the Primordial Beast of Pride wanted to say no at first, but its own pride did not want to spoil it. The own pride of the Primordial Beast of Pride made it basically impossible for it to decline the contract as it placed itself in a pedestal.