并非
bìng​fēi HSK7

is not

并非 (並非) bìng​fēi
is not adverb
a formal way to say 'is not', combining the adverb 'not at all' 并 bìng and the negative copula 非 fēi.
not really adverb
really isn't

成功并非偶然。

chéng​gōng bìng​fēi ǒu​rán.

Success is not accidental.

Frequency
Movie subtitles
30.4 per million appears in 11% of films
Written text
51.9 per million

Details
HSK 2.0
Level 6
HSK 3.0
Level 7

Sources
Definitions
CC-CEDICTAI-generated definitions
Frequency data
SUBTLEX-CHBCC Corpus (BLCU)