Brontë's speaker in "Remembrance" isn't your typical weepy widow who pines away for the one she lost. She lingers over those emotions in the beginning but then learns to check those "tears of useless passion" and strengthen herself "without the aid of joy." So she's pretty tough, especially for the Victorian era when strong women weren't all too common in poetry, mainly because the published poets of the time were mostly men.
Her first-person voice makes her emotions and later her consolation feel all the more real to us without burdening us with too many personal details that could potentially limit the poem's meaning. She kind of lingers and moves with the elements, too, whether she's hovering over those mountains or moving with the "world's tide." And since her emotions come to us in such a natural and fluid way, due to the poem's wavy iambic pentameter and wavy imagery, we get the feeling that she's being rather honest about it all.
By revealing some of her anxieties and questions over her remembrance and that "Sweet Love of youth," we feel like she's being real without trying to inflate her faithfulness or devotion too much. In fact she even admits that she may forget to "love thee" because life is always bringing new hopes and desires. And even if she did seek that "empty world again" there'd be no point since she'd be looking for something that's not there and she'd only drink "deep of that divinest anguish" again. No sense doing any of that, right?
So the speaker is also highly logical about the pain that most people would be overwhelmed by. We might even feel as if she's growing up right before our eyes, starting with that "Sweet Love of youth" and then evolving into a stronger, more experienced version of herself that's still able to recall that love without wallowing for no reason. Even if we were feeling bad for her in the beginning, we're mighty proud of her by the end as she denies those impulses to throw herself into an early grave.