  Using a variational Monte Carlo method, we investigate the nematic state in
iron-base superconductors based on a three-band Hubbard model. Our results
demonstrate that the nematic state, formed by introducing an anisotropic
hopping order into the projected wave function, can arise in the underdoped
regime when a realistic off-site Coulomb interaction $V$ is considered. {\color
{red} We demonstrate that the off-site Coulomb interaction $V$, which is
neglected so far in the analysis of iron-base superconductors, make a dominant
contribution to the stabilization of nematic state. We calculate the doping
dependencies of the anisotropic properties such as the unequal occupation of
$d_{xz}$ and $d_{yz}$ orbitals, anisotropies of kinetic energy and spin
correlations, and show that they are all suppressed upon electron doping, which
are consistent with the intrinsic anisotropies observed by optical spectrum
measurement and ARPES experiments.
