I have a question which, so far, no Christian has answered
to my satisfaction. I find it hard to believe that God exists.
I look around at the world we live in. There is so much pain
and suffering. If there is a God, as Christians obviously
believe, how can you tell people that He loves them?
You have brought up a very deep question. As we look at the evil world we live in with its diseases, death, and pain; it is hard to understand how God could allow this to continue.
Well, rest assured, friend, there is an answer to your question.
While there are many explanations, we will simply address the two that are at the root of the issue. The first reason for God's allowance of human suffering is the issue of dominions. The second, although self-contradictory at first, is the pure form of love which God bestows upon man (bear with me, I will explain).
About dominions... Originally, this earth was given to Adam. In his sinless state, Adam was the ruler of this planet. It was his dominion. In Genesis we read of Adam tending the garden, naming the animals, and performing other administrative and care-taking kinds of tasks. Sadly, when Adam fell prey to Satan's temptation he lost his immortality, his place in the garden, his sinless nature, AND his dominion over the earth.
Naturally, the dominion of earth went to the victor of the skirmish (temptation) - to Satan, of course. In Job 1:6-8, God calls for a heavenly meeting. Satan, who was cast out of heaven, is allowed to be present as the representative for the planet earth.
Now, here's where the love of God becomes evident. God hates the thought of man's suffering, and so He enacts the plan of Salvation. God now knows our suffering from first hand experience. Hebrews 2:14-18 says that because Christ suffered as we suffer, He is able to "succour" (comfort) us.
Now, ask yourself, what did Christ accomplish by coming here and dying for us? Did He plan to buy back a PLANET from the Devil with His blood? NO! The Devil's free-will decision had not yet been completely allowed to run its course. Christ bought INDIVIDUAL SOULS with His blood.
The second point is our ability to exercise free choice. God is all about love. And love, in its purest form MUST allow itself to be unreturned.
Imagine that a person has the capacity to cast some sort of "love spell" over another person. By doing this, they are assured that the object of their affections will have no choice but to adore them. How long will it take before the spell caster becomes dissatisfied with this unnatural love? It would probably be a safe wager to say it wouldn't last long. True love is only satisfied if it is WILLINGLY returned.
With this in mind, picture a loving God. He creates angels. He loves the angels. He desires the angel's love in return. He gives them the FREEDOM to NOT love Him as a result. Now, if God destroyed the Devil the moment he sinned, would that be FREEDOM? Certainly not! God is bound by His own code of love to allow Satan to carry out his choice to its full extent. Only then, could God show His intelligent universe the truth about the Devil's words and about love.
Let's bring it home even further. God creates people. He loves people. He desires our love in return. But again, we are given the FREEDOM to choose NOT to love Him. Choose God and His love, and you find the strength to endure the Devil's dominion.
So, oddly enough, the very thing that you find as a "proof" there is no loving God (the state of our world), is the very thing which truly shows the purity of His love for us. He loves us enough to risk our freedom of choice.