The unique N(BF3)(4)(3-) trianion, which is prognosticated to be the first small long-lived covalent gas-phase trianion in the literature so far, is theoretically examined in detail. High-level ab initio methods show that the T symmetric system is long-lived with respect to fragmentation and metastable with respect to electron emission. To estimate the lifetime of the N(BF3)(4)(3-) trianion with respect to electron emission, we have calculated the repulsive Coulomb barrier and used this potential to compute the lifetime in the framework of Wentzel-Kramer-Brioullin theory. The estimated lifetime is markedly longer than 5 mus, and we predict the N(BF3)(4)(3-) trianion to be observable in a mass spectrometer experiment. The longevity of the trianion with respect to electron emission can be explained by the unbound electrons caught in a negative charged sphere of fluorine atoms.