Zhème dà de shì, gōngsī kěndìng huì chóngxīn kǎolǜ.
For something this big, the company will definitely reconsider.
Tips
grammar
肯定 is versatile - it can be an adverb ('definitely'), adjective ('certain'), or verb ('to affirm'). As an adverb it goes before the verb: 他肯定知道 (He definitely knows). The opposite is 否定 (to deny/negate).
