When sharing the gospel, frequently I hear, “How could a good God allow evil into the world?”
Although there are many ways to respond and several views on the issue within Christianity, I usually respond like this:
The question almost makes it sound as though evil is this rabid dog that God released into the world to bite everyone. This is not the case; rather, God allowed his created beings to make choices. In allowing for choice, God did create the potential for evil. Had He not done that, we would not be having conversation; we would be robotic and therefore incapable of asking why questions. However, you have already acknowledged that there is much evil in the world. Interestingly, in the Bible, Jesus equates lust with adultery and hate with murder. Is murder evil? Is adultery evil? Based upon all of this, have you contributed to the evil in the world?
I would hope there would be more interaction between the individual and me, but at least you can see my line of thought. I try to see every potential objection to Christianity as an opportunity to speak to hearts, trusting that the Holy Spirit is working.