This spelling would be the French name Séraphine; in French, the accent does not determine stress but the pronunciation of the E.
There are several different ones, with é, which English speakers often mispronounce as “ay” and è, which makes a very similar to sound to the E in Sera, as the more common ones.
The stress in french words and names is always put on the last syllable.
So Séraphine would still be se-ra-FEEN.
So based on that I would simply spell the name Seraphine.
Personally, I slightly prefer Seraphina but even more so Serafina, which has a bit more warmth to it and feels more lively in general.