RobH_en_tn/gen/16/07.md

the angel of Yahweh

Possible meanings are 1) Yahweh made himself look like an angel, or 2) this was one of Yahweh's angels, or 3) this was a special messenger from God (some scholars think it was Jesus). Since the phrase is not well understood, it is best to simply translate it as "the angel of Yahweh" using the normal word that you use for "angel."

Shur

This was the name of a place south of Canaan and east of Egypt.

wilderness

This can be translated here as "desert." The wilderness area she went to was a desert.

my mistress

This was a title for Sarah that showed her authority over her servant, Hagar. This can also be translated as "my owner."