Ok so easiest way is to take 3 levels of hex crafter magus and take this at your 3rd magus
levelhttps://www.d20pfsrd.com/classes/base-classes/magus/magus-arcana/rite- publishing-magus-arcana/stalwart-ex/
Stalwart (Ex)
Prerequisite: Magus hexcrafter archetype
Benefit: A hexcrafter magus can use mental and physical resiliency to avoid certain attacks. If she makes a Fortitude or Will saving throw against an attack that has a reduced effect on a successful save, she instead avoids the effect entirely. This ability can only be used if the hexcrafter magus is wearing light armor, medium armor, or no armor. A helpless hexcrafter magus does not gain the benefit of the stalwart ability.
hope that helps :)
