As Elise was a celebrity to a certain degree, giving her such a high priced engagement ring, she would always wear it, since it was a magic tool in shape of a daily article, plainly causing the surroundings to catch sight of it.
It was something you could expect to cause rumors quite soon.
Even if I were to be dragged into a dispute between nobles afterwards and was suddenly abandoned, would they be able to let me be left high and dry?