not necessarily
US /nɑːt ˈnes.ə.ser.ɪ.li/
UK /nɑːt ˈnes.ə.ser.ɪ.li/

1.
不一定, 未必
used to say that something is not always true or not true in every situation
:
•
Being rich does not necessarily make you happy.
富有不一定讓你快樂。
•
Just because he's quiet, it does not necessarily mean he's shy.
他安靜不一定意味著他害羞。