Hi Cesare,
Now this an unusually fine sample of an Italian or South German 15th or early 16th c. knightly ring dagger worth to enter even the most renowned museum!
As you pointed out, the Latin word
amor is spelt in two variations, the second of course being not a grammar but a spelling 'mistake'. I put the word mistake in quote as most craftsmen in those periods of time were neither capable of reading nor writing, and inscriptions like this - as well as on sword blades - had merely become a decorative element in late Gothis script.
Also the use of flower ornaments has nothing to do with early hippie style

but was just a characteristic decorative element.
Concerning the bladesmith's mark, please cf. my notes on a similar mark on one of your lugged spear heads.
Best,
Michael