Janaína is the Brazilian Portuguese form of the Yoruba sea goddess Yemanjá (Iemanjá) — venerated in the Afro-Brazilian Candomblé religion. February 2nd is her annual festival on the beach in Bahia.
Janaina is widely used in Brazil.
Janaina does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Janaina reduce to 5, The Seeker. This is a traditional interpretive system, not a factual claim about the name.