Hindi: How are you?
Tum Kaise hain ho? (how are you?)
Aap Kaise hain? (how are you ?(with respect) )
Aap log kaise hain?(how are you people?)[Need special review for this line]
[correct]
by the way aap kaise hain will also mean to 'all' if u indicate to them in while having conversation.
Main theek hoon(I am ok)
Main achii achchhii hoon ( I am good)
main is pronounced मैं (I) and mein is pronounced as में (in). Please notice that both are PRONOUNCED DISTINCTLY DIFFERENT. Avoid writing mein instead of main.