Reassuringly, well, as reassuring as calling someone a lycanthrope can be, "You're a lycanthrope dear. I don't have a sense that you're what the Welsh call a werewolf. It's ok. It really is. Now that you know, you can manage it. I know there are some who can manage it quite well. Just need to find out what works best for you, and your alter-ego. Let's start with some basic facts. So, how many mornings in a row do you wake up in strange places every month? And how many mornings has it been since this most recent full moon? We need to understand what the immediate problem is, and then come up with a plan for the next month."
(Three nights every lunar cycle; tonight will be the second full moon night.)
Sinmore snuffles and wipes her nose on the sleeve of her dress. "I don't know. It all started when we met the talking Lioness in the forest. But since then maybe...three times a month at least I wake up somewhere strange or with muddy feet and shredded bedclothes. But a lycanthrope? No...no! That can't be! I'm...I'm the daughter of Surtur! How can this happen?"
It seems she does know, probably knew or suspected all along, but never allowed herself to acknowledge it.
"How many more nights do you think you have this month?" Sophronia presses her, and then takes note of the time...Awareness 3 + Per 2 + Die roll of 5=10. "What are your art specialties? What are you willing to do to secure yourself so you don't cause additional harm?"
Sinmore is confused and distraught at the questions, she also looks exhausted after the revelation. "Uh...one? Maybe two nights? Ignem and fire, Creo are my greatest arts. I don't want to do more harm, but...binding me will be difficult!"
Indeed, and I have slim chance of warding you as a human. Sophronia contemplates, "I only discovered you when I added a Corpus requisite to my search. I am unsure if that is because you had already reverted to human form, or if it is something that is necessary always." Sophronia attempts to recollect some bits of Magic Lore that might be pertinent: Magic Lore 1, +Int 2 +die roll of 8=11.
"And if you are just an animal, eve a large one, do you have any might when transformed, or do you maintain your magic resistance related to your forms?"
((How much time do we have before moonrise?))
Sinmore is so distraught she doesn't seem to notice the part where Sophronia admitted scrying on her... 
"I...I don't know, I've never seen it...me! I've never remembered anything about it...except dreams, but nothing that comes to mind."
((Sinmore knows a decent amount of Magic Lore also, but was in denial until now, is there anything she can recall?))
You get an inexplicable urge to go outside and stare at the sky just before moonrise when it's full. Sometimes you lose all three days of the full moon, and sometimes you're conscious during daytime hours. But you always wake up naked and with a bad case of heartburn and a nasty taste in your mouth, that none of the books on Magic Lore ever describe. And you generally have bad diarrhea, or constipation followed by diarrhea, afterwards.
Oh-- and you sometimes find bits of wool stuck underneath your fingernails and bits of bone in your teeth. 
Soprhonia will look on the ground and see if a round pit could be dug out anywhere. And she'll also check the location for privacy...
Sinmore tries to discreetly tell of the symptoms she's been having and will literally throw her considerable weight and strength into whatever task is necessary, including digging a pit.
"Is there a cure? Tell me there's a cure! I don't want to live with this, I want it gone!" she says over and over. "Oh, and I'm fire proof, don't expect that to change, I wouldn't use that in your precautions."
"I'm sure we can search for a cure, but such a task would be a quest that will transform you as surely as you transform at the rise of the full moon. But we don't have time to consider that right now."
Ok, time to go digging. Base 3: Control or move dirt in an unnatural fashion for 10 cubic paces. R:Touch. +1 D:Mom, T:Circle about 1.75 paces across for a 4th level effect. CS: is Re 10+3 +Te 1+ Int 2 + Aura 5=21, divided by 5 is 4+. Idea is to dig down in layers of about a foot at a time in a circle as deep as Sophronia can without fatiguing herself. She'll start a secondary hole next to it when she can't reach and keep going. IF the soild doesn't look stable, she'll abandon that track. Shouldn't take too long to find out if this is going to work.
I don't think Momentary will do it. It would have to be a base level for instantaneous transport, rather than just gradual movement, for Momentary to be sufficient duration. (The ReCo guidelines are much clearer than ReTe, IIRC). Might be easier to take the lower base at concentration.
I don't have my book at work, will check at home.
Think of it as a big shovel kicking everything in the circle out. Creeping Chasm and Crest of the Earth Wave both have effects which happen beyond the casting period.
If that's not good enough, a concentration duration with another +1 for size to 100 cubic paces, on a wider circle 4 paces wide, (so she doesn't have to do it more than once) will push the effect level to 10. 21 + 2*die roll of 5=31, divided by 2 is 15.5.
She'll dig a hole that is 4 paces deep, that's a total of 50 cubic paces. Finesse total of 4=Int 2+Finesse 2+die roll of 0, no botch. Might need to do some fine tuning to make the sides straight up and down to prevent climbing.
Either of you have any applicable skills regarding animal knowledge?
Nope, Sophronia's social, not a beast mistress. And then there's InAn(Co) of 32/16/6...
That's a negative on the animal skills or knowledges.
The hole is dug.
You're in marshlands, though, so the ground is far too soft to get straight edges, regardless of your Finesse totals. It might be straight for a few minutes, but it'll all sink back in pretty quick.
"Well, that was ill advised." She probably saw water before getting too deep, and once she saw water, she would've stopped.
"Do you have a secure room in your sanctum? Something that could be barricaded? I could attempt to ward you, but I'm not confident of success."
Just a reminder in case qcipher has forgotten-- Sinmore has never established a sanctum. She has been staying in guest quarters in the Great Hall, (where the proximity of her Gift upsets the covenfolk) and she has been using the guest laboratory in the tower when necessary.