How to tell a guy to improve his physical appearance and manners without hurting his feeling or sounding mean?

So, basically, his face is cute, but everything else needs work? You need to be with a different dude.

You don't. Break up with him and move on. Never waste your time on a grown man who needs to be taught basic life skills and manners. These are fundamental expectations. He is not mature enough to be in a relationship if he can't do the minimum to care for himself and be considerate to others. If you want a companion who stinks and has no table manners, get a dog. It may actually listen to you.

tell him, being honest is a great quality, if a person can't take it, then they aren't for you. too sensitive.