The word "behold" alerts us to a new person in the story. Your language may have a way of doing this. Alternate translation: "There was a Canaanite woman who came"
"a woman who was from that region and who belonged to the group of people called Canaanites came." The country of Canaan no longer existed by this time. She was a part of a people group that lived near the cities of Tyre and Sidon.
This phrase implies that she is requesting that Jesus heal her daughter. Alternate translation: "Have mercy and heal my daughter" (See: [[rc://en/ta/man/translate/figs-explicit]])
Jesus was not David's literal son, so this may be translated as "Descendant of David." However, "Son of David" is also a title for the Messiah, and the woman may have been calling Jesus by this title.
This can be stated in active form. Alternate translation: "A demon is controlling my daughter terribly" or "A demon is tormenting my daughter severely" (See: [[rc://en/ta/man/translate/figs-activepassive]])