Her name is confirmed to be "Tiara" from this video, though in that video she sounds like she says "Tiara Augusta" in her voice clip when selected, which is speculated to be her surname.

LoneShadowStar said in comment #2610178:

Her name is confirmed to be "Tiara" from this video, though in that video she sounds like she says "Tiara Augusta" in her voice clip when selected, which is speculated to be her surname.

The official English spelling of the name has just been revealed to be “Tialla”.