stealthily, in secret

love letter

to secretly send a love letter

(formal) Female third-person singular pronoun; she, her, girlfriend

(colloquial) a girlfriend (a female partner in a romantic relationship)

(literary) they (about women or girls)

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

to send; to dispatch / to see off, to take (somebody somewhere), to escort / to play back / (linguistics) to add okurigana / to pass the time / to see off a deceased person