Due to the charge transfer effect at the contact of transition metal (TM) and MoS2, the use of ferromagnets in MoS2 based spin transistor is not suitable. On the other hand, β-Ni(OH)2 is known to be a layered type material with antiparallel Ni spins in alternate layers. Here, an ultrathin layer of antiferromagnetic β-Ni(OH)2 is grown on the MoS2 surface to achieve complete ferromagnetism with giant coercivity (2925 Oe). The origin of this ferromagnetic ordering is the reduction of Ni spin moments in Ni(OH)2 layer adjacent to MoS2 surface due to charge transfer from S to Ni. The use of antiferromagnetic layered type material to achieve ferromagnetic ordering with giant coercivity is a new concept to realize perfect two-dimensional (2D) ferromagnets which have major advantages due to the huge change in coercivity with thickness. © 2016 American Physical Society.