assiduity

noun2

1. •
   Great and persistent toil or effort.

   • Her coyness was conquered by assiduity, and at last she consented to resign the treasure of her charms to my passion. — 1769
2. •
   [in the plural] Constant personal attention, solicitous care.

   • I will stay even contrary to your wishes; and though you should persist to shun me, I will make my respectful assiduities atone for the levity of my past conduct. — 1773