A method for sealing a fitment to a flexible container comprising the steps of: providing a flexible container formed of flexible film and having a plurality of panels (20, 21, 22, 23), and a neck configured to be connected to a fitment, via a multiseal, the multiseal formed from the plurality of panels being sealed at the neck and comprising a top edge, a bottom edge, a plurality of sealing surfaces, and a plurality of flaps; providing the fitment, the fitment comprising a base surface; placing the fitment in the neck, wherein the multiseal is provided around the base surface such that the multiseal and the base surface are complementarily aligned; providing a plurality of primary seals (130, 131) of the multiseal via engagement of the multiseal by a plurality of primary sealing jaws, wherein the primary sealing jaws form the primary seals (130, 131) at the sealing surfaces and flaps of the multiseal, wherein the sealing surfaces are sealed to the base surface and the flaps are folded toward and sealed to the sealing surfaces; providing a plurality of secondary seals (140, 141, 142, 143) of the multiseal via engagement of the multiseal by a plurality of secondary sealing jaws, wherein the secondary sealing jaws form the secondary seals at the sealing surfaces and flaps of the multiseal, wherein the secondary seals (140, 141, 142, 143) overlap with the primary seals (130, 131), and wherein the secondary seals (140, 141, 142, 143) are located substantially closer to the top edge of the multiseal than to the bottom edge of the multiseal; and providing a plurality of tertiary seals (150, 151) of the multiseal via engagement of the multiseal by a plurality of tertiary sealing jaws, wherein the tertiary sealing jaws form the tertiary seals (150, 151) at the sealing surfaces and flaps of the multiseal, wherein the tertiary seals (150, 151) overlap with the primary seals (130, 131) and the secondary seals (140, 141). providing a flexible container formed of flexible film and having a plurality of panels (20, 21, 22, 23), and a neck configured to be connected to a fitment, via a multiseal, the multiseal formed from the plurality of panels being sealed at the neck and comprising a top edge, a bottom edge, a plurality of sealing surfaces, and a plurality of flaps; providing the fitment, the fitment comprising a base surface; placing the fitment in the neck, wherein the multiseal is provided around the base surface such that the multiseal and the base surface are complementarily aligned; providing a plurality of primary seals (130, 131) of the multiseal via engagement of the multiseal by a plurality of primary sealing jaws, wherein the primary sealing jaws form the primary seals (130, 131) at the sealing surfaces and flaps of the multiseal, wherein the sealing surfaces are sealed to the base surface and the flaps are folded toward and sealed to the sealing surfaces; providing a plurality of secondary seals (140, 141, 142, 143) of the multiseal via engagement of the multiseal by a plurality of secondary sealing jaws, wherein the secondary sealing jaws form the secondary seals at the sealing surfaces and flaps of the multiseal, wherein the secondary seals (140, 141, 142, 143) overlap with the primary seals (130, 131), and wherein the secondary seals (140, 141, 142, 143) are located substantially closer to the top edge of the multiseal than to the bottom edge of the multiseal; and providing a plurality of tertiary seals (150, 151) of the multiseal via engagement of the multiseal by a plurality of tertiary sealing jaws, wherein the tertiary sealing jaws form the tertiary seals (150, 151) at the sealing surfaces and flaps of the multiseal, wherein the tertiary seals (150, 151) overlap with the primary seals (130, 131) and the secondary seals (140, 141).