Grammar check please?

Hi,

Can you advise me which one is better word for these sentences, please?

These two countries have been trying to unite/unify together. (Both words are verbs)

All the shops have uniform/united/unified price, doesn’t really matter where you go. (There are all adjs)

Could you also tell me if I am correct in these grammar, please?

I scare of water. (Ungrammatical)

I am scared of water.

I fear of water. (Ungrammatical)

I am feared of water.

I have a fear of water. (It acts as noun)

Thanks in advance.