The word(s) "knowest" appears 13 time(s) in 12 verse(s) in Quran in Muhammad Pickthal translation.

(11) And when Our revelations are recited unto them, thou knowest the denial in the faces of those who disbelieve; they all but attack those who recite Our revelations unto them. Say: Shall I proclaim unto you worse than that? The Fire! Allah hath promised it for those who disbelieve. A hapless journey's end!

(12) O Prophet! When ye (men) put away women, put them away for their (legal) period and reckon the period, and keep your duty to Allah, your Lord. Expel them not from their houses nor let them go forth unless they commit open immorality. Such are the limits (imposed by) Allah; and whoso transgresseth Allah's limits, he verily wrongeth his soul. Thou knowest not: it may be that Allah will afterward bring some new thing to pass.