How is there no guarantee if I claim that I guarantee to repay it?
A claim is not a guarantee. It's just your word, and believe it or not, people don't always keep their word - esp when they have $2,000 they don't want to repay.
For example, a letter from your HR verifying you are past probation and that your wages will be garnished if you default. Or a lien on your vehicle until the debt is paid off. These are actually things that force you to repay, making it more likely you will.
Unless you are willing to provide an actual guarantee that you will repay, stating it just makes you look like a scammer.