Saina is from the Sanskrit sainya (army) — "of the army, warrior." Saina Nehwal (born 1990) — Indian badminton player; in 2012 became the first Indian (of any sport) to win an Olympic medal in badminton, taking bronze at London 2012.
Saina 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 Saina reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.