@Fahima4 I understand, but try to not to overly concern yourself with this. If you do your best to make sure guests are comfortable, that all is working properly in the listing, that it's really clean, and that you communicate well with the guests, that's all you can do, and you can't do anything about someone deciding to leave a bad review, so there's no point worrying yourself over it before it's ever happened. I've never had a bad review in almost 3 years of hosting, although reading these forums, you'd think all guests are just waiting to have the opportunity to trash talk people's listings, which isn't true.
One of the dangers of fearing bad reviews, especially for new hosts, is that you might get a guest who's really demanding, hard to please, and acts entitled. You bend over backwards to try to appease them, thinking that will ward off a bad review, but that's not the case. Guests like that will not leave a good review just because you went out of your way for them, quite the opposite, because they are basically miserable people who only care about themselves. So keep that in mind- if you get a guest like that, don't do any more for them than you would for any other guest, and if they have endless complaints and demands, be firm, friendly and professional.
"I'm so sorry, XX, but as you can read on my listing page, I don't offer use of the washing machine. There's a laundry just down the block that does a nice job."
"Yes, I know the Wifi is sometimes iffy- that's why I mention it in my ad. All the neighbors here have to put up with the same thing. It's the only server in the area. I know it can be frustrating."
"I'm sure your cousin is very nice, but there is an extra guest charge on my listing, so if she wants to spend the night, we can just add that to your reservation right now and get it squared away."
The funny thing is, people (not just guests) who are demanding and entitled just act more so when you give in to their unreasonable demands. They are used to bullying and getting their own way, so standing your ground and not being a pushover actually can lead to them respecting you more.
Of course, if a guest is just asking for an extra blanket, to borrow some milk until they get to the store,or anything else reasonable, a good host will try to accomodate.
There's nothing wrong with going out of your way or doing something extra special for a nice, respectful guest, who will likely leave a good review anyway, just don't think a troublesome guest will be encouraged to leave a good review just because you caved to their every demand.
I'm sure you'll do fine, relax and enjoy the hosting journey. It's a learning curve for sure, and we've all gone through it.