Question

Which set of four words do not all rhyme with each other:
1. pause / pores / pours / paws
2. ewe / you / yew / blue
3. awe / ore / or / oar
4. vain / vane /van / vein

Answer 1

Perhaps the set of four words not rhyming well with each other is :
    3.    awe ore or oar....     The first word is not rhyming/sounding well with the other words..

Rhyming sets.
   1. pause == paws ....   pores == pours
   2 .  ewe  == you...    yew == blue
   4.  vain , vein , vane , van.. quite close sounds .

Answer 2

The third set of words does not rhyme or matches with other set of words. In the third set, the word awe is not at all rhyming with other three words. And, in the fourth set of words, the word van does not rhyme at all with other three words. Other than this, in the second set of words the word blue also does not rhyme with other three words. In this set of words, the first set of words rhymes and matches each other very clearly.
Hope you understood my answer