"kind of" and "sort of" mean "to some extent" or "part of". For example, you could say a sentence like "Part of me wanted to be a doctor, but then I decided to become a teacher instead". It would mean the same thing as "I kind of wanted to be a doctor, but then I decided to become a teacher." It means that a person is torn between more than one option (part of them wanted to do ____, they wanted to be _____ to some extent". Does this make sense? :)

It can also be said "I sort of wanted to be..." but sorry I have no idea how I should explain it...

The whole sentence would make answering your question easier. The phrase "kind of" is more or less equivalent to the phrase "sort of". Examples: "I'm kind of sleepy today." "This music is kind of boring." Slang versions are "kinda" and "sorta". Hope this helps!