do I have a winning chance?

My ex boyfriend wants to sue me for $800 to have a dent on his car repaired. I accidently hit his car on a post 9 months ago. He gave me verbal permission to drive his car. I had non owners insurance at the time. I asked my ex if he wants it repaired. I offered to have it fixed, but he declined. We broke up a few months later and now he is charging me $800 in repairs. Do I have a winning chance? We did not have any witnesses, but he is manipulative and he can convince his friends to testify for hI'm. I have text messages that confirms he declined my help. He also made a statement that makes it seems like he is upset that I have a new boyfriend. I am agreeing to help him with half the expense but he does not want it. He wants me to pay full. He wants to have his car repaired so he can trade it in for a new car. He is being very bothersome.