expression
indefinitely; for a long time; forever
Emphatic form of いつまでも, stressing that something continues without end or for an extremely long time. Often used in wishes, promises, or complaints about something that never changes.
あなたのことはいついつまでも忘れません。
I will never forget you, no matter how much time passes.
この幸せがいついつまでも続きますように。
May this happiness last forever.
いつまでも is the standard form meaning 'forever' or 'indefinitely'. いついつまでも is a more emphatic, slightly literary or emotional variant that stresses endlessness.
Reduplication of いつ (when) plus まで (until) and も (even), literally 'until when-when even'. The doubling of いつ intensifies the sense of endless time.