為さる is read as なさる (nasaru) and means to do.
なさる
nasaru
なせばなる
if you have a mind to do something, you can do it
しそめる
to begin to do
しおおせる
to accomplish
かわせ
exchange (e.g. foreign)
ため
affecting
いせいしゃ
statesman
かわせそうば
exchange rates
なす
to change into
かわせかんり
exchange control
かわせぎんこう
exchange bank
ために
because of
なさい
do ...