Apology Letter For Lost Item
Dear {Recipient},
Please accept my sincere apologies for losing your {item}. You trusted me to keep it safe and I failed. I know how much that {item} meant to you and I feel really bad for letting you down.
If you could tell me where you purchased it, I'll check if it's still available and buy you a replacement. Otherwise, I'll just pay for it instead.
Sincerely,
{Your Name}