After all there is no such thing as afterall and let's not talk about. We know the meaning of after all, don't we? It means in spite of considering contrary views or expectations.
The phrase ‘after all’ means ultimately, or in the end.
“I bought a ticket to the gala, but unfortunately I couldn’t attend after all.”
Afterall is a misspelling that happens when people assume it’s a compound word rather than a two-word phrase.