ことだし / ことだから

Usage

because; since ~.

Expresses guess / inference (only with nouns)

Because of an actual situation

それは、私にとって重要なことだから答えて It is very important for me, so please answer it

明るい彼女のことだから、どこへ行ってもすぐ友達ができるでしょう Since she has a bright personality, she is able to make friends no matter where she goes