No, they only share a suffix.
Fleetest or neatest would rhyme with sweetest. Some other near rhymes might be sleepless and speechless.
Cutest would rhyme with lutist and flutist. It would be a near rhyme with truest.
I ran into him thirty times.... he is the cutest, sweetest celeb ever. I wish I could be his girlfriend.
It depends on what you want to say. If you mean "sweetest" in the sense that he is the "most affectionate" and "cutest" person, then, I would say: Eres el novio más tierno del mundo. If you mean "sweetest" in the sense that you are eating him and he is sweet (as opposed to sour or bitter), then I would say: Eres el novio más dulce del mundo.
That is the sweetest thing! He is the sweetest boyfriend I've ever had. Candy is the sweetest of those foods.
That is the SWEETEST thing. You are the sweetest. etc.
abab
sweetest
The cutest boy would be whoever you think is the cutest. Everyone has their own opinion about someone.
prodigy is the second cutest materafact he is the cutest
No, the word cutest is not a noun, it' an adjective, a word that describes a noun: cute, cuter, cutest.
Cutest is the superlative form of the adjective cute.
In my opinion anything sugary is the sweetest
U2 sings the sweetest thing