Formal:
* Bahut-bahut dhanyavaad: This is the most common and formal way to express "Thank you very much."
* Aapki bahut kripa hui: This translates to "Your kindness is greatly appreciated."
* Aapke anant dhanyavaad: This is a very formal and poetic way to say "Thank you immensely."
Informal:
* Bahut dhanyavaad, yaar: "Thank you so much, friend"
* Dil se dhanyavaad: "Thank you from the heart"
* Aapne bahut badi meherbani ki: This translates to "You have done a great favor."
Other options:
* Aapki bahut madad hui: This translates to "You helped me a lot."
Remember:
* The best way to express a "massive" thank you depends on the context and your relationship with the person you're thanking.
* Adding words like "bahut" (very), "kafi" (quite), or "bahut bada" (very big) to your thank you can emphasize the depth of your gratitude.
* You can also use gestures like a namaste (bow) or a hug to further convey your gratitude.
Let me know if you want to learn more about expressing gratitude in Hindi!