I am as brave as he. = He is not braver than I.

I am ashamed of his conduct

I am capable of doing it.

I am Confident to win. = I am confident of win.

I am going to market.

I am not as brave as he. (comparative) = He is braver than I.

I am sure of his success.

I am sure it is a mistake 

= It is a mistake and I am sure of it.

I am sure that she will succeed in the examination

I am sure that soon photography is my favourite pastime = I am sure that soon  photography will be my favourite pastime.

 I am a university student.

I can not be false to my friend.

I can not help doing this. 

I can not make out what he says.

I cannot make out these four boy.