Actually it's already been proven that they colony of Roanoke had assimilated. "Before he had left the colony, White had instructed them that if anything happened to them, they should carve a Maltese cross on a tree nearby, indicating that their disappearance had been forced. As there was no cross, White took this to mean they had moved to "Croatoan Island" (now known as Hatteras Island)" Also around the same time white Indians "mysteriously" began to appear.

Source: Wikipedia.

There’s no proving anything for sure - the fact that White believed the colonists had relocated doesn’t necessarily make it so. It’s more likely a mixture of things (starvation, assimilation, annihilation) caused the disappearance of the Roanoke colonists, in my opinion.