Need an honest opinion what to do

I am preparing for SSC. I met one school guy on social media app 1.5 years ago. We hardly spoke to each other in school but we started talking about career, life and our bonding started growing. I had never thought I would develop such a meaningful bond with a school guy after 5 years of leaving school. He and I had a common friend(girl) but now the guy and my friend are not in contact(you will be able to decode reasons later). 2 months ago I met that common friend of us along with one more girl who was also my batchmate in school. The girl after knowing that I am in contact with that guy shared something which shook me completely. She said that the guy was mad behind her and she had to block him in order to get rid of him. She even said that he used to emotionally blackmail her to accept her proposal. I could not believe my ears because how much I have known him and he had shared things with me, he just liked her because the girl had given certain hints to him which made him believe that she likes him. She even used to praise him infront of his friends and reject other guys saying that no one is like him. But after they broke contact, she has spread this story defaming him. Since she is very beautiful also and tells her story with conviction, everyone has believed her. At present, none of the friends of that guy are in touch with him due to this fake news. Now he has become my good friend and he likes me, instead loves me but I am not able to convince myself because of his market reputation. Every now and then, I am reminded of the story which the girl narrated infront of me. My mental peace is at stake because I think the guy is not wrong here. What should I do? Continue friendship with him or break contacts or accept his proposal? Please suggest.