This is way over-simplified.
Marissa seems to have been independently created in the USA in the 19th century by blending
Mary and
Melissa. Maritsa and
Maritza are respellings in Spanish speaking countries of the Slavic and Hungarian name
Marica. In those languages the letter "c" is pronounced like "ts" is in English.
Maritza would be more often found in Latin
America than in Spain because in most dialects of Latin American Spanish, "Z" is pronounced like "S".