This is the 536th most frequent Swedish word.
gärna
"Gladly," "happily," or "willingly."
In this context, 'gärna' conveys a polite suggestion or permission for the listener to take an action.
Du kan gärna sitta där.
You are welcome to sit there.
In this usage, 'gärna' conveys a flexible attitude or willingness to accommodate someone else's preference.
Vi kan gärna äta middag tidigare om det passar dig.
We can gladly have dinner earlier if it suits you.
Here, 'gärna' expresses a willingness or readiness to assist someone.