I'm deeply grateful to you. 我对您深为感激。
He found her comments deeply irritating/offensive. 他觉得她的话让人觉得很不舒服/及其无礼。
We don't want to get too deeply involved with these people. 我们不想和这些人深交。
After 20 years of marriage, they're still deeply in love. 结婚已经20年了,他们依然深爱着对方。
Synonym: profoundly