She always asked if others wanted tea. It tended to throw people off-guard, and she knew how to use that to her advantage. She made whoever it was feel welcome, like they were in a place that was willing to be friendly and helpful. It made them feel important, that the oldest princess was serving them her tea.
Tea was calming, and, if brewed correctly, could dull the mind a bit, make one a bit more open to talk. She could fight, better than her sister, but talking was a much neater way to deal with problems that occurred. It was her style to be tidy.
When she called people to the table, she had the advantage, one that she wasn't afraid to press. The upper hand was essential, and offering tea gave her that advantage. She was the hostess, they the supplicant. It was all a delicate balance.