In case someone stole your bitcoin or you lost it, you won't be able to get it back.
Is this true?
What are your knowledges about this?
You need to understand the blockchain and bitcoin mechanisms. They are anonymity and cannot be tampered with, so when your coin is stolen, as long as it is confirmed, then your coin is not yours. This is why the key needs to be kept well. After being obtained by others, the coin will not belong to you.