That actually can be answered in one sentence. Because God loves everybody regardless of whether it is someone who hates themselves or who hates others. John 3:16 of the Bible has a reason for saying, “For God so loved the world...”
He proved that love in the greatest way He could have ever proved it.
All of us are sinners and a holy God has to punish sin. But God proved His love by allowing His perfect Son to die in our place on a cross, be buried and rise again. Through trusting Him alone to save us, we receive His free-gift of eternal life. John 3:16 continues by saying, “that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.” What better way to say, “I love you”?
The good news does not stop there. As someone who loves you even though you hate yourself, once you trust Him as Savior He will help you look at yourself differently. There are all kinds of reasons people hate themselves. They may not be able to get over the mistakes they have made, might not like their physical appearance, might be distraught by what they feel are handicaps and disadvantages about themselves, or feel that for any number of reasons that they will never amount to anything. God can change all that and help you look at yourself through His eyes.
A great example is a man by the name of Paul from the New Testament. Before he came to Christ, he watched in delight as the Christians he’d brought charges against were stoned to death. As he put it, “I persecuted the church of God.” (I Corinthians 15:9) He would have had every reason to hate himself. From what we know through historical records, his physical appearance wasn’t anything to brag about either! But when God saved him, He saw himself through God’s eyes instead of his own. He was able to say, “But by the grace of God I am what I am”. (I Corinthians 15:10)
Let God save you. Then let Him help you one day at a time to see yourself the way God sees you – as a beautiful person He made and wants to use to His glory.