The context of the following conversation is When Sydney needed an extra voice for harmonies at her friends wedding she asked her mother and Sydney and her mom sang together.:
Sydney says I'm glad my mother could help us with the harmony because it sounded really weak..
The friend responds She loves singing right?.
Sydney responds Yes, I had to get rid of a singer because she kept singing out of tune and was messing up the song for others so I needed someone to fill in..
The friend responds Well she harmonises very well with you..