From what I remember, I think it was a manhwa.

The female main character was killed in her world for supposedly trying to poison her younger sister (who it seems planned the whole thing to get the main character killed). After her death she reincarnates into another family in the same world with an older brother and is mute(?) for a while before eventually speaking at what I'm pretty sure was her birthday party (or some party).

There's a timeskip and she discovers that she has light spirit summoning magic and then, after she and her brother get poisoned, she heals her brother by summoning a spirit.

I think in the first life she had black hair and green eyes, and then after being reincarnated she looked a lot like her sister (the villain) in the first life with light (maybe white) hair and I think either gold or blue eyes.

From what I remember, I think it was a manhwa.

The female main character was killed in her world for supposedly trying to poison her younger sister (who it seems planned the whole thing to get the main character killed). After her death she reincarnates into another family in the same world with an older brother and is mute(?) for a while before eventually speaking at what I'm pretty sure was her birthday party (or some party).

There's a timeskip and she discovers that she has light spirit summoning magic and then, after she and her brother get poisoned, she heals her brother by summoning a spirit.

In the second life, because of her spirit summoning magic, she became a saintess. Her brother also swore some kind of oath to her to protect her I think?

I think in the first life she had black hair and green eyes, and then after being reincarnated she looked a lot like her sister (the villain) in the first life with light (maybe white) hair and I think either gold or blue eyes. In the first life she also had quite a few siblings, including the villainess.

From what I remember, I think it was a manhwa, but the female mc was killed in her world for supposedly trying to poison her younger sister (who it seems planned the whole thing to get the mc killed). After her death she reincarnates into another family in the same world with an older brother and is mute(?) for a while before eventually speaking at what I'm pretty sure was her birthday party (or some party). There's a timeskip and she discovers that she has light spirit summoning magic and then after she and her brother get poisoned she heals her brother by summoning a spirit. I think in the first life she had black hair and green eyes, and then after being reincarnated she looked a lot like her sister (the villain) in the first life with light (maybe white) hair and I think either gold or blue eyes.

From what I remember, I think it was a manhwa.

The female main character was killed in her world for supposedly trying to poison her younger sister (who it seems planned the whole thing to get the main character killed). After her death she reincarnates into another family in the same world with an older brother and is mute(?) for a while before eventually speaking at what I'm pretty sure was her birthday party (or some party). 

There's a timeskip and she discovers that she has light spirit summoning magic and then, after she and her brother get poisoned, she heals her brother by summoning a spirit. 

I think in the first life she had black hair and green eyes, and then after being reincarnated she looked a lot like her sister (the villain) in the first life with light (maybe white) hair and I think either gold or blue eyes.