“Scared” is the past tense and past participle of the verb “to scare” = to cause someone to feel fear. As a past participle we can also use it as an adjective as a synonym for “afraid”.

Afraid is an adjective: someone is afraid of something. We also use afraid in the expression “to be afraid that X”, which we use in two ways. 1. Sometimes it simply means “I fear that”. 2. Sometimes we say this when we answer a question or give information to suggest that we are not responsible for the answer or information, or that we can’t do anything to change the answer or information. For example, “I’m afraid that I won’t be able to visit you tomorrow.” = I can’t visit you tomorrow”, or “I’m afraid that you will have to talk to X to resolve this issue” = “I do not have be the authority to help you resolve this issue, all I can do it tell you who has the authority.”

Fear is either a verb or a noun. As a verb, to fear something = to be afraid of something OR to be scared of something. As a non-count noun fear is the name of the emotion. As a countable noun fears are the things that a person fears.

They more or less have the same meaning but I can help explain context. "I'm afraid" and "I'm scared" mean the same thing but more people say the second one. However "I'm fear" makes no sense. Fear can be used in sentences like "I have a fear of heights" but you cannot say "I have a scared of heights". To make that sentence grammatically correct you'd have to say "I'm scared of heights" or "I'm afraid of heights" I hope that helps