必至

1. Origins, structure, and basic meaning

• Structure: 必至（ひっし） expresses a judgment that an outcome is unavoidable.
• Basic usage: Use it when saying a future outcome is inevitable, as in 変更は必至だ.

2. Common pitfalls and similar expressions

• The same reading with a different meaning
  • 必死 is also read ひっし, but describes a desperate, all-out effort.