answer for this one detail?

Whensoever I made the discovery, it laid a heavy burden on me. And
yet, comparing it with the far heavier burden that I afterwards
took up, it does not seem to me now to have been very hard to bear.
In the knowledge that I did love her, and that I should love her
while my life lasted, and that I was ever to hide my secret deep in
my own breast, and she was never to find it, there was a kind of
sustaining joy or pride, or comfort, mingled with my pain.

But later on, - say, a year later on, - when I made another
discovery, then indeed my suffering and my struggle were strong.
That other discovery was -

These words will never see the light, if ever, until my heart is
dust; until her bright spirit has returned to the regions of which,
when imprisoned here, it surely retained some unusual glimpse of
remembrance; until all the pulses that ever beat around us shall
have long been quiet; until all the fruits of all the tiny
victories and defeats achieved in our little breasts shall have
withered away. That discovery was that she loved me.

She may have enhanced my knowledge, and loved me for that; she may
have over-valued my discharge of duty to her, and loved me for
that; she may have refined upon a playful compassion which she
would sometimes show for what she called my want of wisdom,
according to the light of the world's dark lanterns, and loved me
for that; she may - she must - have confused the borrowed light of
what I had only learned, with its brightness in its pure, original
rays; but she loved me at that time, and she made me know it.