Which sounds better?

Which sentence sounds better?

-I have thoughts that there would be mutual benefits for both of us if we could
explore new business opportunities together in IoT, Connected Cars, etc.

-I believe that there would be mutual benefits for both of us if we could explore new business opportunities together in IoT, Connected Cars, etc.

I think the first one sounds a bit unnatural and the second one is better, but some of my co-workers think the opposite. Does 'have thoughts' in the first sentence sound okay to you?

To have thoughts often implies that the thoughts come unbidden and unwelcome to mind, i.e., that they are intrusive thoughts. This is different from thinking, which implies a voluntary and controlled mental process. Gently convince your co-workers that "I believe" (or even "I think") is the better choice.

While you're at it, you may drop "for both of us." The word mutual implies the reciprocal nature of things, here between the first person (the speaker) and the second person (the spoken to).