Saint Martin vs Saint Maarten

Saint Martin and Saint Maarten both are nouns.

Word	Noun	Adjective	Verb	Adverb
Saint Martin	Yes	No	No	No
Saint Maarten	Yes	No	No	No

As nouns, Saint Martin and Saint Maarten are synonyms defined as:

Saint Martin and Saint Maarten: an island in the western Leeward Islands; administered jointly by France and the Netherlands

Other synonyms of Saint Martin include Sint Maarten, St. Maarten, St. Martin.

Saint Martin (noun)	Saint Maarten (noun)
an island in the western Leeward Islands; administered jointly by France and the Netherlands	an island in the western Leeward Islands; administered jointly by France and the Netherlands