What your book (probably) meant is that the hydrogen bonds in fumaric acid, being intermolecular, holds the molecules together more strongly, so it has a higher boiling point than maleic acid, whose hydrogen bonds are intramolecular and thus cannot hold the molecules together as strongly as the hydrogen bonds in fumaric acid.

What your book (probably) meant is that the hydrogen bonds in fumaric acid, being intermolecular, does a better job of holding the molecules together, so it has a higher boiling point than maleic acid, which instead, displays intramolecular hydrogen bonding which doesn't hold the molecules together just as well.