Don't give up 不要放弃 Bùyào fàngqì

It should be "Búyào" ,coz if two forth tone come together, the first one will be pronounce the second tone.

道路可能会很长 Dàolù kěnéng huì hěn zhǎng.

长 has two pronounciation. The first is zhang, which means grow. The second is cháng,and that means  long.
你可能看不到希望 Nǐ kěnéng kàn bù dào xīwàng. 

again, it should be the second tone, bú
但不保证 Dàn bù bǎozhèng.

但有信心它的存在Dàn yǒu xìnxīn tā de cúnzài.

你将达到成功 Ní jiāng dádào chénggōng.

haha ,am sure you were just typing it wrong.

有决心Yǒu juéxīn.
付出努力Fùchū nǔlì
堅持到底 Jiānchí dàodǐ
不要放弃 Bùyào fàngqì

Don't give up 不要放弃 Bùyào fàngqì

道路可能会很长 Dàolù kěnéng huì hěn zchǎng.
你可能看不到希望 Nǐ kěnéng kàn bù dào xīwàng.
但不保证 Dàn bù bǎozhèng.
但有信心它的存在Dàn yǒu xìnxīn tā de cúnzài.
你将达到成功 Ní jiāng dádào chénggōng.
有决心Yǒu juéxīn.
付出努力Fùchū nǔlì
堅持到底 Jiānchí dàodǐ
不要放弃 Bùyào fàngqì

The road may be long.
And You may not see hope
There is no guarantee 没有保证
But have faith that it is there. 但相信它就在那儿。
You will reach success.
Have the determination.
Put in the effort.
Never give up till the end
Don't give up.