Expresses a deep, often painful longing for someone or something, frequently romantic. Sense 2 (love ardently) is a natural extension of this yearning.
She pined for her lover and wrote letters every day.
2
suffix, ichidan verb
do eagerly; do with restless anticipation
Attaches to the -masu stem of a verb to express doing something with intense eagerness or anticipation. This is a literary and somewhat old-fashioned suffix.