Thank you so much! I appreciate it.

Not exactly. For example, "hope" is a noun. If you add "-less" you get "hopeless." "Hopeless" is an adjective that means "having no hope." If you add "-ness" to that, you get "hopelessness." "Hopelessness" is a noun meaning "the state of having no hope." It doesn't work with every word, but there are many it does work with.

There are hundreds of them. Just do a search.

So, by adding less and ness (the other one I forgot), we automatically convert any word into an adjective?

Yes, "careless" and "carelessness" are both acceptable words. "Careless" is an adjective and "carelessness" is a noun.