Kono Yuusha Ga Ore Tueee Kuse Ni Shinchou Sugiru

The story begins when the goddess Listarte summons a hero to help her hard mode video game-like world. The hero, Seiya, is exceptional in every way, but he is incredibly cautious. He does things like buy three sets of armor (one to wear, a spare, and a spare for the spare) and go full power against weak slimes (just in case). From ANN.