Formal:
* आपके लिए शुभकामनाएँ (aapke lie shubhkamnaye): This literally translates to "best wishes for you," and is a very formal and respectful way to end a letter or email.
* आपके प्रति आदर सहित (aapke prati adar sahit): This translates to "with respect for you," and is also a very formal and polite way to end a letter or email.
Informal:
* शुभकामनाएँ (shubhkamnaye): This simply means "best wishes," and is a more informal way to end a letter or email.
* आपका प्यार (aapka pyaar): This translates to "your love," and is a very informal and friendly way to end a letter or email. It's often used between close friends or family.
Other options:
* भवदीय (bhavadīya): This is a common ending for letters in Hindi, similar to "Yours sincerely" in English. It's quite formal.
* आपका भाई (aapka bhaai): This means "your brother," and is a very informal and friendly way to end a letter or email, typically used between men.
The best option for you will depend on the specific situation and your relationship with the recipient.