Why do I get jealous over a girl even though I don't want to be with her at all?

 Both "how is it" and "how's this" are correct, but they have slightly different meanings and uses.

"How is it?" is a general question that can be used to ask about the state or condition of something. For example, you might ask a friend "How is it?" after they have tried a new restaurant, or you might ask a coworker "How is it?" after they have been working on a difficult project.

"How's this?" is a more specific question that is used to ask about something that the speaker is holding up or pointing to. For example, you might ask a friend "How's this?" after you have put on a new outfit, or you might ask a customer "How's this?" after you have shown them a product.

Here are some examples of how to use each phrase in a sentence:

How is it?

How is the new job?

How is the food?

How is your day going?

How's this?

How's this new haircut?

How's this new dress?

How's this for a view?

Which phrase you use depends on the context and what you are trying to ask. If you are asking about the general state or condition of something, then you should use "how is it." If you are asking about something that is specific and visible, then you should use "how's this?"

I hope this helps!