@Bari51 welcome! Hope your hosting goes well.
Regarding guests who request disocunts: I would say generally, don't host them. However, I have made exceptions (without agreeing to further discounts). Keep in mind that many social media sites are providing tips for getting discounts, so they may not realize it's potentially offensive to hosts.
The deposit is a lie. You can ask guests to pay for damage, but unless they agree, you're probably not getting the money. Airbnb doesn't collect any money or put a hold on a credit card to cover this amount.
The host guarantee is real, but it's very difficult to collect on it. Remember that you must submit at least a preliminary claim before the next guest checks in. If you don't, you definitely won't get anything. You don't have to have all your quotes from contractors, but you do have to begin the process. If you don't, it's guaranteed that the claim will be rejected, no matter how much supporting documentation you have. Read the terms and conditions and make sure you understand what you need to do, and understand that if you do, you may still get nothing. Only actual damages will be covered: extra cleaning or smoking inside is unlikely to be covered unless you can prove that you have incurred costs from cleaners or cleaning equipment - and even then, you're unlikely to be covered.
Make sure you have your own insurance! Hosting has been great for me: I hope it works well for you also! Just make sure you know and fully understand what you're getting into.