Simcha is from the Hebrew śimḥā (שִׂמְחָה — joy, gladness, celebration). Simcha Holtzberg (1969-2008) — modern Hasidic Jewish figure. Simcha Goldstein — Hasidic Jewish figure. Princess Simcha — Jewish heritage naming.
Simcha 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 Simcha reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.