Something like Hoshi no Koe, because she is traveling at light speed she experience time slower than he does while he grow older or Emanon's Wanderings, she left the seeds in the village to come back for them in a later incarnation and then one last time after the village had been destroyed.

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"The oldest and strongest emotion of mankind is fear, and the oldest and strongest kind of fear is fear of the unknown"

urrm so what are you looking for exactly? time difference? or time manipulation?
if its the latter then maybe Gyakusou Shoujo - Owaranai Natsuyasumi

Perhaps Toki wo Kakeru Shoujo - Tokikake

Kimi ni Shika Kikoenai is really beautiful

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in need of romance?
uncommon, sad, sweet

Psyren they keep traveling in time...

manga about time? you mean like time paradox?
All I find from searching based on that categories are Let's Lagoon and Mirai Nikki: Paradox, alternate stories of Mirai NIkki

for time traveling, all I can remember now are Boku wa Beatles and Zipang

Or you can try Hotel, it's faith doesn't bounded by time, great one shot...

Agreed, it is a great manga. Add it as another example.

Time loops and paradoxes can work, though im more looking for time perspective. Ill still check them out too. Thx all, anyone else?

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"The oldest and strongest emotion of mankind is fear, and the oldest and strongest kind of fear is fear of the unknown"

If you read novels you absolutely have to try Hakomari.

I can't really think of any manga exactly like what you asked (it's something I definitely found more often in books or other media than manga), so those suggestions could be a bit off but I thought to mention them anyway:
Steins;Gate
Kurozuka
Vampire Juujikai

Another one which could theoretically fit would be Spice & Wolf but the different conception of time between Holo and Lawrence is a topic that only occasionally comes out, not really the main topic of the story (and it's definitely more present in the books than in the manga). I doubt it's what you really want, but it's a very good manga anyway.

Hope this can help, but definitely Hakomari is the only title which truly fits your request imho.

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What I like in Trivial Pursuit style. Pick your category:

The fifth story in Erotic Horror, the girl is stuck in the same day. Or perhaps Omae ga Sekai wo Kowashitai nara but the time aspect is only revealed near the ending. Also try this: the 3rd story in 100% Gokuama Kareshi!, a really bittersweet story.

Tsubasa Reservoir Chronicles-xxxHoLic

just started to read Pandora Hearts and somehow it's kinda fit with your desc...