A boy told himself that he was too busy to break up anyway, but when I sent him a message, she replied slowly or even didn't.

Because you are seldom emotional, you will be very emotional. Since you are not suitable for each other, then this boy is not suitable for you, because his heart never regards you as a person who needs to be cared for and treated with care. People who don't even reply to messages won't send you messages. I think people who don't respect you always say they are busy, but I think they will have time to check their mobile phones and send messages when they are busy.