Respect and Regard are synonyms, so we need a synonym pair. Stain-Spotless, Ruin-Repair and Regret-Rejoice are all antonym pairs. Detest and Despise (the intended word) are synonyms, so option 3 fits.
Note: The option 'Detest : Despite' appears to contain a typo for 'Despise', which is the synonym of Detest; we have solved it as intended.