疑いなく :without (a) doubt
そちらで :at your end
こちらで :at this end = on my(our) side
9月1日の週 :during the week of September 1st
~の違い :the difference in(between)~
そちらで :at your end
こちらで :at this end = on my(our) side
9月1日の週 :during the week of September 1st
~の違い :the difference in(between)~