必然
bìrán · HSK 3
inevitably
必 = must + 然 = so; 'must-be-so' → inevitably, certainly
必 carries the sense of 'must/necessary' and 然 means 'so/thus/in that way'. Together they form 'must-be-so', i.e. something that follows necessarily — bound to happen.
必 — heart 心 + slash 丿
Originally depicted a handle or marker driven through something, suggesting a fixed standard. The form was later reanalyzed as 心 (heart) with a stroke through it, reinforcing the sense of inner certainty. It came to mean 'must' or 'certainly'.