(Al-battu fī al-istimrār fī al-shiddah) — "Decisiveness in continuing through hardship."
If you clarify the intended meaning, I can refine it further. For now, the most direct correction of your transliteration into proper Arabic script is: lbt alastmar fy alshdt
But if you intended a more common phrase like (steadfastness in continuing through hardship), here is the corrected proper form: here is the corrected proper form: