Here are some examples of how "fain" can be used:
* "He was fain to help her." (He was glad to help her.)
* "I fain would go, but I cannot." (I would gladly go, but I cannot.)
* "They were fain to leave the city." (They were willing to leave the city.)
While "fain" is still recognized as a word, it is rarely used in modern English. If you want to express the same meaning, you can use more common words like "gladly", "willingly", or "eagerly".