So I wanna start this game but...is really that hard as it sounds?
I'm not in the "mood" for hard games at the moment,so it's better doing this later on?

How many "easy" survival horror games are there?

Well,Silent Hill and Penumbra saga are easy enough.
But the thig who scares me is the "time" factor.

I didn't find Amnesia to be particularly hard. I mean, I'm not even sure you can die through sanity loss, you just have to put up with increasingly irritating interface screw. If there's a sanity breakpoint that causes you to commit suicide like in the Call of Cthulhu game, I certainly never reached it. And the monsters have such short attention spans you're only in danger of physical death from the invisible water-monsters or if you get trapped in a closet or something.

Well,Dark Corners of Earth was hard :|

I believe a patch fixed the default difficulty. It was punishingly hard apparently.

I played it without patch ages ago...killing Dagon was a nightmare,but also the final "running" section :(

I remember playing it also and vaguely remember dying a-lot inside a factory with a fish-man running away and I having to chase him.. and tentacules everywhere that would simply drain my life... and after (or before) this, a runaway in a car incredibly hard again... Don't know where in the game I was, but it might have been near the end.

Yes,I remember the factory too,where there was a "blob" that follow you.
Also the "escape" from the hotel was very hard.

I'd say "borderline broken" rather than hard; it's basically down to dumb luck how badly you get injured during that sequence. I felt that that game went downhill badly once guns were introduced; a pity, because the hotel escape scene was brilliant.

Amnesia has almost no challenge whatsoever.

The designer's deliberately eliminated anything they felt could start to be traditionally challenging. Particularly with the sanity meter and the AI. Originally there were consequences for losing sanity, but they didn't like how it felt and decided to make it an ambient feature instead. As far as the AI goes, monsters will actively try to KEEP from finding you, but will ACT like they're trying to hunt you down. And yeah, they simply despawn after awhile. Plus, there's no setback for dying. Or rarely, at least.

I found only the Justine expansion hard,because you can't save,and if you die,you must repeat all the starting crates section :\

Really? I haven't played the expansion.

Amnesia took a lot out of me. It was just smoke and mirrors, but damn... I was honestly terrified while playing.

Yes,Justine is hard.It's only about 40 minutes long,but at the ending of this dlc there is a chasing sequence really hard,if you die you must restart from the beginning.