Main reason +we believe+ that will...

[Bansha]

I want to formulate this sentence correctly...

Those are the main reasons +we believe+ that will make this project very interesting for everyone who takes part in its realization.

Should I split the "we believe" part with commas?

Should I put it like this maybe;

Those are the main reasons that +we believe+ will make this project very interesting for everyone who takes part in its realization.

 

[xqby]

I'd like to back up a bit first, because I don't think that the sentence is correctly constructed even before you try to add in "we believe."

"Those are the reasons that will make this project very interesting..."

I'm not sure I would say reasons themselves make projects interesting. I would suggest that either you have reasons which lead you to believe the project will be interesting, or that you have goals/incentives/coursework that will make the project interesting.

 

[nizarm3allem]

I would say: "We think that those are the main reasons that will make this project very interesting for everyone who takes part in its realization."
The verb think is different of the verb believe.

 

[entangledbank]

Commas are needed in your first version. It contains a relative clause in 'the main reasons that will make . . .'; if 'we believe' followed straight on from 'reasons' it would look like those words formed part of a relative clause. It would be like 'the main reason we believe you is that you are an expert'. So, to show that the words 'reasons we believe' don't go together, you need to use commas.