I feel that you title was misleading. You gave zero reasons why you think the god you believe in is loving. If he is willing to send you to hell for your choices is he loving, or vengeful?

Ask yourself, if there was no evil inside our hearts, would we be suffering?

Yes. We suffer not only because of evil, we suffer from diseases, disasters, freak accidents and so on and so on.

So, suffering in this world is caused by men only. Unfortunately.

Not true for the reasons above. There are so many causes of suffering that come from the world around us, not ourselves as men. For instance, why would a loving god allow a baby to die on the first day of her life?