Alma 31:4

Now the Nephites greatly feared that the Zoramites would enter into a correspondence with the Lamanites, and that it would be the means of great loss on the part of the Nephites.

The Nephites were very scared that the Zoramites would join with the Lamanites. That would cause big trouble for the Nephites.

The Nephites were deeply worried that the Zoramites might form an alliance with the Lamanites. That could mean disaster for their people.