Well seems kita wants to kill himself because he felt his life is hopeless which hes getting hope again after hes clearly falling in love with her. So its seems she might find her life hopeless aswell for some reason whsts your guys bets on the reason. I think it relates with her husband some how.
Basically her depression isn't as straightforward as his and though her existence is a key to cure his, his existence doesn't cure hers.
For him it seems like he just had no hope that someone would be on his side. For her on the other hand... I'm guessing she just has no hope that living could ever become truly enjoyable.