Chrysanthi’s name day is March 19, the feast of Chrysanthos and Daria.
Churches that follow the Old (Julian) Calendar keep the same feast on April 1 of the civil calendar. See everything commemorated on March 19.
The saint behind the name

Chrysanthos and Daria
March 19, Martyr, Χρύσανθος
Sts. Chrysanthos and Daria were martyrs of Rome in the third century. Chrysanthos, the son of a pagan noble, came to faith in Christ through the reading of the Scriptures; when his father arranged his marriage to Daria, a learned pagan woman, Chrysanthos won her to the faith, and the two lived in purity, devoting themselves to prayer and to bringing others to Christ.
Name days: Chrysanthos, Hrysanthos, Daria, Chrysanthi
Also celebrating on March 19
These names share the feast, many of them other forms of the same name:
Chrysanthos, Hrysanthos, Daria
What to say on a name day
The Greek wish is Χρόνια Πολλά (Chronia Polla), “many years.” A call or a short message on the day is what people remember. See name day wishes you can send and what a name day is.