EXCLUSIVE

Joanna Krupa's vagina is in a league of its own when it comes to scent ... according to her estranged husband, who's defending her against Brandi Glanville.

Romain Zago dropped the sweet, sweet compliment earlier this month during a deposition in the now-infamous smelly vagina legal battle between Joanna and Brandi.

According to docs, obtained by TMZ, Romain told Brandi's attorney -- "If you want to know the answer to this stupid comments from your client, (Joanna's) vagina smells amazing. And I swear on God, Jesus, my father, my brothers."

Brandi's lawyer asked Romain if Joanna smells better or the same as the other women -- and he said, "Better than any other woman in the world." Ringing endorsement, for sure.

Romain also accused Brandi of being a horrendous bully who damaged his marriage.

Joanna filed to divorce him just 4 days before the deposition, and he STILL testified pro vajayjay!