This is the 3514th most frequent Spanish word.
garantizan
"They guarantee."
Here 'garantizan' indicates an assurance provided by 'ellos' (they) about the building's safety.
Ellos garantizan la seguridad del edificio con sistemas modernos.
They guarantee the safety of the building with modern systems.
In this sentence, 'garantizan' is used to show cause and effect, where efforts lead to success.
Los esfuerzos constantes de los ingenieros garantizan el éxito del proyecto.
The constant efforts of the engineers guarantee the success of the project.
Here, 'garantizan' expresses an obligatory assurance provided by the laws in favor of everyone's rights.