According to the translation given here, Sumanah means "beautiful mind" throughout i.e in all the applications the word is having the same meaning.
But I have a small book published by the Ramakrishna Mutt called "Sri Mahishasura Mardini Stotram" (consisting of three Stotras - the one discussed here, Bhavani Ashtakam by Adi Shankara and the Amba Stotram by Swami Vivekananda) according which the various Sumanahs found in the line have different meanings.
Following are the meanings of the various words in the line:
Ayi - O Mother, 1st Sumanah (of superior qualities), 2nd Sumanah - of
the residents of Divyadhama or of heavens, 3rd Sumanah - grown in
their gardens, Sumanohara Sumanah - beautiful Parijata flower.
So, the overall meaning of this half verse is rendered thus:
O Mother! You are endowed with exquisite beauty of the flowers, that
are grown in the gardens of the good-souled residents of the heavens
However, the meaning as per the already linked website is simply this:
Ayi Sumanah-Sumanah-Sumanah Sumanah-Sumanohara-Kaanti-Yute
11.1: Salutations to You O Divine Mother; I Invoke You; Whose Beautiful Mind is United with a Charming Appearance