With that plan in mind, Linsley connected his power with the World Will and was immediately granted the right to use the Voice of The World.
The Voice of The World was like an announcement that could be heard by anyone in Terra or anyone with origins in Terra.
Of course, it could also be controlled so that only specific people would hear it, but in this case, Linsley didn't need to do that, as he wanted everyone to hear his voice since he would be declaring himself as the World God of Terra who eliminated the Outer God.
As for whether they would believe it or not, the fact that he could use the Voice of The World, along with the sudden disappearance of the Outer God's lackeys and the annihilation of the Outer God Association, were undeniable proofs.
As the World God, the World Will would also validate his claim to those magical girls and mecha drivers from the resistance.