expression
vice versa; the reverse is also true
Used to state that a relationship or statement holds in the opposite direction as well. Often follows a clause and is equivalent to 'and vice versa'.
AがBを必要とするなら、逆もまた然りだ。
If A needs B, then vice versa.
彼は私を信頼している。逆もまた然りだ。
He trusts me, and the reverse is also true.
Similar meaning, but 逆も真なり is more formal and often used in logical or mathematical contexts.
A set phrase composed of 逆 (reverse), も (also), また (again), and 然り (classical copula meaning 'so' or 'true'). Literally 'the reverse is also so'.