Does pure monotheism forgive sins, including major ones?

Complete Tawhid necessitates repentance and abstinence from all sins, because sins undermine the perfection of Tawhid. Those who possess this pure and complete Tawhid are forbidden from the Fire. Pure Tawhid leaves no room for sin; for it encompasses such love, reverence, glorification, fear, and hope in Allah alone, that it necessitates the washing away of sins, even if they were as much as the earth's fullness. As for those whose Tawhid is incomplete and who die persisting in sins, they are subject to the Lord's will.