既然你不喜欢我，那就以后不要再见面了。

Jìrán nǐ bù xǐhuān wǒ, nà jiù yǐhòu búyào zài jiànmiàn le.

Since you don't like me, we won't meet again.

既然你已经有了决定，我就不再多说了。

Jìrán nǐ yǐjīng yǒu le juédìng, wǒ jiù bù zài duō shuō le.

As you already have made a decision, I won't say any more.

既然这个方法不行，那就再找另一个方法继续做吧。

Jìrán zhège fāngfǎ bù xíng, nà jiù zài zhǎo lìng yí gè fāngfǎ jìxù zuò ba.

Since this method doesn't work, we have to find another method to continue working.