You’ve written a line that is recited at the start of Kausagga/Kayotsarga (standing or seated “abandonment of the body” meditation) in Pratikraman.

Original (Prakrit, common Śvetāmbara paddhati transliteration) “Saddhae mehayae dhiye, dhāraṇā anuppehāe vaḍḍhamāṇie, ṭhāemi kaussaggaṃ.”

Simple meaning (arth) “With firm faith and exalted, focused intellect; with concentration that is uninterrupted and steadily increasing, I establish myself in Kausagga (Kayotsarga).”

Notes on tradition

• Śvetāmbara usage: the word is “Kausagga” (Prakrit form). The line is said just before beginning the Kausagga posture during Pratikraman/Sāmāyik.
• Digambara usage: the practice-name is “Kayotsarga.” Meaning is the same—stilling the body and turning awareness inward toward the soul (ātma), letting go of bodily movements and external concerns.
• Minor wording/pronunciation variants exist across prayer-books, but the sense remains: resolve for continuous, growing concentration and then enter Kausagga/Kayotsarga.

Essence This verse is a sankalp (intent): strengthen faith and focus, make the mind steady and unbroken, and then perform Kausagga/Kayotsarga to purify karmas through stillness and inner awareness.

For a simple overview of Pratikraman and Kausagga, you can refer here: