I'm sorry to + (verb)

Saying you are 'sorry to' expresses a feeling of sympathy or regret.

Here are some examples:

"I'm sorry to be so late."
"I'm sorry to hear about your sick mother."
"I'm sorry to waste your time."
"I'm sorry to make you feel so sad."
"I'm sorry to frighten you."
"I'm sorry to disagree with your decision."
"I'm sorry to call so late."
"I'm sorry to admit what I did."
"I'm sorry to end this relationship."