BS”D
Leib is lion in Yiddish and not heart. It is a pure Germanic word; the surname Loeb (including the Moroccan Loeub which is actually borne by descendants of Ashkenazim who ended up in Morocco!) is a different Germanic version of this word.
Aryeh Leib follows the same pattern as Dov Ber, Menachem Mendel, Tzvi Hirsch, Kalev Hunt etc – Hebrew original for koidesh, Yiddish variant for daily use.