Hello. I don't know what the underlined part means in this context below.
Please help!!! Thank you.
The stepsister's blue eyes filmed with tears, and she bit her lip with vexation, to miss all the gaiety. She tried to hide this, as if she needed to cough, but Yetiffe understood her. However, for the evening to pass pleasurably, as it should at her mother's table, the stepsister must be too busy to have a chance to sit down to dinner with the company.
In order for the evening to pass enjoyably for everyone, as was only right when one dined with her mother, ....