If you asked Celine she would have said that Rumi was a relatively easy child.
(if anyone else had been there to attest they would likely claim very differently. Rumi was quite demanding at certain times, felt her emotions very strongly, and asked many, many questions. Some would describe her as a brat)
Celine however was doing this all for the first time and all alone. She knew mostly what not to do and her and Rumi were kind of just doing it together:
Having a child who let it actively be known when she needed attention, time, or soothing was better than trying to gage it herself. After all she was constantly terrified of both overstepping and not being enough. Having a child who would come to her and ask ask ask about hunters and her mother and such was easier then trying to decide when to broach things. She could take Rumi to the old tree and sit with her and answer all her questions to the best of her ability (while being age appropriate).
It wasn’t always the best. Rumi would get overwhelmed. She was a bit of a biter as a child and would try the childish mischief but she had an open face. Couldn’t keep a secret for long but when she was obviously full of guilt and feeling bad enough already Celine knew to diffuse the situation until they were either both giggling or just hugging.
Sure, Rumi would beg and whine to go to the Teddy Bear Museum for weeks until Celine had time but she mostly behaved when they got there and they had a wonderful time.
Everyone who comes around later gets the idea that Rumi was the most Polite Perfectly behaved child until Celine lets slip an anecdote about the time Rumi tried to paint a chicken and then climbed the roof to get out of talking about it. (She was maybe 7 years old). Or the time she tripped a not particularly nice man at a gala. Or the time Celine had to leave her with a last minute caretaker and Rumi had a meltdown so strong that furniture had to be replaced. (That one was complicated)
“but I thought you said Rumi was a super wonderful kid?”
“oh she was.” Because there’s no way she could see Rumi as anything less than wonderful.