Would you please explain about wanna, gotta, ain't?
When we speak, we often collapse "want to" to sound like wanna.
"I want to get an early start tomorrow" will sound like "I wanna get..." However, unless you are writing dialogue in fiction, and want your character to deliberately sound uneducated, don't use it in writing. (My advice. Others may disagree.)
It's the same with "got to" sounding like "gotta." Don't write it - just realize that it's how it will sound when people are speaking quickly.
The same applies to "going to" which will sound like "gonna." "I'm going to watch the football game" will probably sound like "I'm gonna watch..." (You didn't ask about "gonna" but it's the same as wanna and gotta, so I threw it in.)
"Ain't" is considered nonstandard in modern speech. It's used to substitute for "am not" or "is not."
Unlike wanna, gotta, gonna, using "ain't" it the use of a different word. Instead of saying "I'm not" or "he isn't" it's "I ain't" or "He aint." It's not just a how our speech sounds.
If you use it in writing dialogue, you will use it to show a lack of education, e.g., "I ain't gonna do that, and you can't make me." (Others may disagree.)
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.