Is it time to tell him?

This guy and I went to school together and we have reconnected at the age of 18. He is one of the best human beings I have ever met. I have a huge crush and he said he likes personality not looks ( I’m self conscious) I want to tell him so badly that I like him but I did it before ages ago and he just brushed it off. He’s a very popular guy so I feel like I might just be another girl to him. But I like him so much. What should I do? He’s sweet and funny and just understanding. But I’m so scared of rejection