All-Consuming Obsession

[The male lead has been in love with her for a long time + rekindled romance + personal growth + a gradual, steady romance]

When they first met, the female lead was innocent and adorable, and the young man was drawn to her radiant beauty.

But a sudden upheaval turned them into strangers.

When they meet again, the female lead has long since shed her gentle, graceful past and become sexy and mature.