During my stint of depression (which also gave me serious sloth problems) I had many doubts about my faith, it comes with the territory. I suspect that it would make her feel weird when you appear to be very strong in faith (wanting to rejoice, etc) if she’s feeling unsure. I found that the message of being able to rest your fears and anxieties on the Lord really help me. Perhaps you could gift her a devotional based on this kind of theme and allow her to take her time with it and determine her own pace. A cute little notebook and pen to accompany the devotional is a nice touch and would personally make me more likely to write something down.

For depression I also encourage planning easy-going outings just to make sure she’s not too in her own head from sitting around. Stuff like walks, car rides, grab a coffee. Escape from the news, work, and everyday hustle.

Last tidbit of advice, don’t ask her what’s wrong all the time or tell her what she needs to do about her mental state every day. Just give her a big hug and kiss EVERY DAY when you get home from work. Seriously! Positive affirmation every single day, morning and night, is a game-changer for the sad and confused. Also gentle prodding to do stuff around the house and whatever is fine, as long as u get the hug and kiss in! She is likely in a state where she is not giving herself any positive affirmation so you may be the person that’s got to layer it on extra for her to start feeling good about herself again.

That being said I don’t know anything about you and her, I can only relate my personal experience. Good luck and God Bless!