It's grammatical, but I don't know if it means what you intend it to mean. It reads as 'If I died tomorrow, what one thing would you want me to know as I died?'
If you mean, what would you want me to know now, before I die, then you would do better to write:
'If I were going to die tomorrow, what one thing would you want me to know now?'
"If" makes it conditional, so "... what would you do?" would be proper.
The correct grammar is "Between you and me."
It is correct.
no_____If the sentence is You do do that (meaning You are in the habit of doing that) the grammar is perfectly correct and the sentence 'does have correct grammar'.
The correct sentence is: "Have you ever traveled before?"
No
shone
was arrested
The correct grammar for the sentence is: "Please note that this letter is merely an inquiry regarding your interest and availability."
The correct sentence is: "Is it supposed to rain?" This is a question formed in the present tense asking about future weather conditions.
There is a mistake in your bill.
No, the correct version of the sentence would be: "Will you wait for me tomorrow?"