Samantha and Garrett met when they were just kids when he moved in across the street. Many years passed and they both moved away pursing their own dreams and careers. Garrett randomly reached out to Sam while she was in college and they began a long distance texting friendship. When Sam graduated college and moved home Garrett was persistent in landing "the girl next door," and kept asking Sam out. Finally Sam gave in and the rest is history.
As their parents would say, they are two peas in a pod. As Sam and Garrett would say, they share one single brain cell. Whatever it is, they are definitely meant to be.