How are you my sister in bengali?

There's no direct equivalent of "sister" in Bengali to address someone in a friendly or informal way. You can use different phrases depending on the context and your relationship with the person.

Here are a few options:

For a close friend:

* Tumi kemon acho? (Formal) - This is the most common and polite way to ask "How are you?"

* Ki khobor? (Informal) - This literally means "What's the news?" and is used to inquire about someone's well-being.

* Tomay kemon lagche? (Informal) - This means "How are you feeling?" and is used for close friends or family.

For a younger person:

* Tumi bhalo acho? (Formal) - This means "Are you well?" and is a polite way to ask how someone is doing.

* Kemon acho? (Informal) - This is the casual way to ask "How are you?"

For a slightly older person:

* Aapni kemon acho? (Formal) - This is the polite way to ask "How are you?" for someone older than you.

Remember that the best way to address someone depends on your relationship with them and the context of the conversation.