As long as he is a decent person, it doesn't matter.
As long as he is kind, nothing else matters.
「いい人でありさえすればそれでいい」＝ As long as he's a good person, I don't mind. / As long as he is a decent person, it doesn't matter. / As long as he is kind, nothing else matters.
ボキャブラリー
でありさえすれば ＝ as long as ～
いい人 ＝ a good/decent/kind person
I don't mind ＝ 私は気にしない、構わない
it doesn't matter ＝ 構わない
nothing else matters ＝ （他の事は）構わない
日本 
イギリス 
