What do i say to a boy i really like that has liked me before?

well this boy i like he was my best friend and that and well i had a boyfriend and also my best friend didn't like the idea of me having a boyfriend and he didn't like him but then me and my best friend had something going on for awhile and then he kissed me and well this left me and my boyfriend relationship very unstable and well now we've ended i've realized i love my best friend and now i don't know what to do because my best friend really did like me and now i like him and well he's scared i'm going to hurt him or something? what do i say to him i've told him that i like him and that but i ended up meeting up with him again and he was like flirting with me big time but yeah i've asked him how he feels and he's like just stuck and i really want to have that chnace with him but i want to prove to him that we would work.. so i need help, any suggestions?