Engagement Ring

Faina is actually in possession of two rings:

A blue sapphire ring inset in silver and diamonds, given to her by Isaac Thomas

A green emerald ring inset in platinum and small diamonds, given to her by Sam Skiles

At the moment, she is in possession of both, but the sapphire ring has been hidden and she is currently wearing the emerald ring... only it's enchanted to appear like the former.

To sum up a dramatic and complicated love story:

Sam was in preparation to propose to Faina when the Ravagers were destroyed and Sam was taken prisoner by Reinare. Faina was unaware of this at the time. He managed to keep the ring throughout everything that followed, as it was kept on the chain alongside his amulet.

Fast forward five+ years later, with both Faina and Isaac believing their ex-boyfriend/best friend to be dead and having dated, Isaac proposes to Faina and she says yes - hence she receives the sapphire engagement ring.

When Faina and Sam reunite on Valentine's Day, under a love potion's spell and unaware that the night was not a dream, Sam is finally able to gift his ring to Faina - who promptly accepts his proposal and replaces the sapphire with the emerald. He takes the ring back when the 'dream' ends, and neither remember the night.

When her memories of that night start returning, Faina can't wear her sapphire engagement ring anymore, and takes it off. Fast forward a bit more, as part of the deal with the Blood Legion, they retrieve the emerald engagement ring from Sam and return it to Faina - who is both bound to and desires to wear it.

But no one knows what was done that night with the emerald ring, nor is she able to wear it without arousing suspicion as to what it is and who gave it to her. So she has the emerald ring spelled with a flimsy illusion by Sundog Books to look like her sapphire ring, so no one will question her or ask about it.

The sapphire ring is just an ordinary engagement ring - no magic on it whatsoever.

The emerald ring is spelled with a flimsy illusion spell so that it appears in every single way to be the sapphire ring. However, the spell is flimsy because the illusion will break and reveal the true ring if Faina ever takes the ring off her ring finger.

There is additional magic on the emerald ring that ties into the bonding magic on the Caged Pendant and Sam's Amulet. But exactly what that magic is or what it does has yet to be discovered.