Sentence:  Then we relapsed into a discomfited silence, and wished we were anywhere else. But Miss Thorn relieved the situation by laughing aloud, and with such a hearty enjoyment that instead of getting angry and more mortified we began to laugh ourselves, and <WSD>instantly</WSD> felt better. 
Meaning of the word marked with <WSD> tags:  At once; without delay. (from 16th c.)