How do I keep him in the friend zone?

I'm in community college and there is this guy that is in two of my classes that I am friends with. He is a nice guy and we talk a lot. He asked for my number and he texts me a lot also. At first it wasn't bad but now he has gotten to the point where he tells me he misses me, he apologizes if he thinks he has said something wrong and he is constantly asking to hangout. I have a daughter and work and school so I told him I don't really have anytime to hangout. He now texts me constantly after school hours way more than he used to, told me that he thinks about what it would be like kissing me and before it used to be just talking like friends would do. Also he asked me in school after class if he could give me a kiss before he left. I kinda got nervous so I was like I have to go to the library and he followed me. I asked him where he was going because he was parked in the other lot on the opposite side of school and he kinda got all nervous and was like oh I'll come to the library too. I said oh I thought you had to leave and he goes oh oh yah I do. In school we are talking with other friends all together outside of class and or we are talking about class and doing homework together so it's fine then because there are other people around. I don't know what to say because I've already tried to make it clear that we are just friends. I don't want things to get ockward because we have two classes together and have the same friends. Also if the teacher ever pairs us together for group work or to work in pairs I don't want it to be ockward. He also told me that he has plenty of other girls that he's friends with but doesn't deep the way about them that he does about me. What do I do or say to him to get him to realize hey we have class together and can be friends but that's it.
How do I keep him in the friend zone?
Add Opinion