If you sympathised with someone, you understood and cared about their feelings, especially if they were having a hard time.
Sympathising with someone is a kind and caring thing to do.
Examples:
She sympathised with her friend when her friend's pet ran away.
I sympathised with my sister when she lost her toy.
He sympathised with the sad boy at school.
The cat sympathised with the sad dog.
The king sympathised with the poor people in his kingdom.
The teacher sympathised with the students who were having trouble with their homework.