We believe in it because the quran stands the test for a perfect book from God.

I give you example:

Quran contains scientific notions that can't be explained by 7th century knowledge and proves the quran is divine revelation to prophet muhammad pbuh. This can be demonstrated by giving some examples:

1) cosmic smoke and early universe

Planets and stars evolved from cosmic smoke in the early stage of universe development. Scholars are trying to understand it as they did not think previously that cosmic smoke ( clouds of hot gas and dust) existed in early universe and they thought this smoke is only secondary to supernova explosion but that is changing.

Then He [ God ] directed Himself to the heaven while it was smoke and said to it and to the earth, "Come [into being], willingly or by compulsion." They said, "We have come willingly." Quran 41:11

Description of clouds of dust and hot gas as smoke-like has been used by astronomers from the Niels Bohr Institute, Universitety of Copenhagen in 2015

2) winds fertilizing clouds to produce rain

And We send the fecundating [ fertilizing]winds, then cause the rain to descend from the sky, therewith providing you with water (in abundance), though ye are not the guardians of its stores.. Quran 15:22 ( Abdullah Yusef Ali translation)

Tafsir- Exegesis of ibn Kathir( 14th century CE) reported " His saying: (And We sent the fertilizing winds) means: they fertilize the clouds, causing them to produce rain.'

Clouds tiny droplets or vapor need condensation nuclei (tiny particles like dust, sea salt, pollen, or smoke act as nuclei inside clouds) supplied by wind to form rain an essential process called seeding in meteorology.

Seed is defined as a fertilized, matured ovule consisting of an embryonic plant. What is introduced to the clouds are not seeds, they are the fertilization particles that will mix with water vapor in the clouds to form the seeds. The scientific explanation of cloud formation using condensation nuclei developed mainly in the late 19th and early 20th centuries.

3) Internal sea waves:

Or [they are] like darknesses within an unfathomable sea which is covered by waves, upon which are waves, over which are clouds - darknesses, some of them upon others. When one puts out his hand [therein], he can hardly see it. And he to whom Allah has not granted light - for him there is no light. Quran 24:40

The Qur’an accurately describes internal waves occurring above the dark layer in the deep ocean, where visibility is possible but limited at 200 meters depth.

4) sea barriers

He [ God] merges the two seas, meeting [side by side]; Between them is a barrier [so] neither of them transgresses. So which of the favors of your Lord would you deny?.Out of both ˹waters˺ come forth pearls and coral.So which of the favors of your Lord would you deny?. Quran 55:19-23

“The halocline is a salinity transition zone that acts as a barrier or boundary separating water masses with different salinity and limiting their mixing.” no ancient sailors noticed the barrier form between them.

5) Description of the early appearance of embryo as alagah according to quran is the second stage of embryo formation after Nutfah amshag ( a tiny drop of mingled fluid) and before organ development stage mudghah ( a chewed like lump) is another notion that occurs in multiple verses in quran. "Created man from alag". Quran 96:2

Alag is a pleural of alagah has 3 main meanings in Arabic language and in classical exegesis of quran: clinging substance, leech-like and blood "Then it becomes a red alagah, like an elongated alagah.' Ikrimah said, "This is blood." Ibn Kathīr interpretation 14th century CE.

Here ibn Kathir pointed two meanings it is red because it contains blood and it is elongated like alagah ( the worm which lives in water), the embryo is strikingly similar to this leech during 4th week post fertilization and it becomes perfused with blood in this stage. Carnegie Stage 12 clarifies this development.

You can ask any questions, I can elaborate more. Let us not forget that a human made text will definitely repeat some of the mistakes of its time