It worths it, "it worth it" or "it is worth it"?

Question

Which one is correct and why? I think "worth it" is an adjective phrase. So what is "worth" then? Example: > You should try spending money on her. **It worths it**. > You should try spending money on her. **It worth it**. > You should try spending money on her. **It is worth it**. Which one is right? The last 2 are not condemned by grammar checker.

Answer 1

You have two choices: It is worth it OR It's worth it. The other options you listed are incorrect.

Answer 2

There are two main usages of 'worth':

A. It can be a noun: What is the worth of your money?

B. It can be a preposition with the sense 'equal in value to': The gym is worth the effort.

In the phrase 'worth it' 'worth' is a preposition.

See https://www.merriam-webster.com/dictionary/worth.