If God send someone to eternal Hell, how is that considered unconditional love?

First of all God love is not unconditional but is a Selfless river than must flow. Second there is no eternal place of torment called hell. The Eternal Fire of the Truth will simply burn up and destroy all illusion along with those who decided to walk in it because it suited their lust and desire and they will cease to exist even in memory. The will not enter into Eternity. God simply gives them their way and He is not concerned with those who walk in the flesh because they only serve a temporary purpose and when they die their bodies are used for energy and nutrient for lower life awareness. God is only concerned about His Spirit offspring on this planet and He allows the flesh to reap the corruption of the flesh but delivers His own from the pit falls. To God those who walk in the flesh are just atoms and nothing more unless they repent are are changed.