What does 'ain't' mean?

How can I use "sure" like this?

"Sure" here means "certain" or "positive". Therefore, you can use "sure" in this way when you are confident about something or asking someone if they are confident about something. Ex: I'm sure I'm going to become a teacher. Ex: Are you sure you want to eat that? It looks rotten.

so the phrase "break a leg" can only be used in a performance?

Yeah, that's right! It's a kind of theatrical slang. Outside of performances and the theatre, it wouldn't quite fit the context, and people may think you're telling them to literally break a leg! Ex: I hope your baseball game goes well. Break a leg! => incorrect usage (X) Ex: I hope the talent show goes well. Break a leg! => correct usage (O)

Why would India abolish the law?

From what I understand, it's due to the large population size in India, and possibly to reduce the number of immigrants in the country! India is the second country with the highest population on earth, the first being China. Due to the conflicts surrounding the country, many people might flee to India for safety.

Could you tell me some alternative words that can replace "delicious"?

Sure! Many synonyms can replace delicious: tasty, scrumptious, yummy, delectable, or mouthwatering. Ex: The ice cream is so delectable. Ex: The smell of hot dogs made her mouth water. Ex: Wow, this is so tasty! You need to share your recipe with me. Ex: This meal was scrumptious. Thank you.

Just curious, but what's the main difference between a "newspaper" and a "tabloid?"

A tabloid can be considered a type of publication, but it's different from newspapers in that they often contain information about scandalous topics or rumors. Newspapers are usually dedicated to reporting news and facts, but tabloids mainly focus on sharing sensational news (usually about public figures like celebrities or politicians). Ex: A British tabloid reported on the popular politician's affair. Ex: I don't read tabloids. I think they rot your brain.