Translation:No couple achieves it immediately.
Since your two translations for 'Ninguna' are 'neither' and 'none', how does my translation come to be incorrect?
I really don't care for these sentences that don't make any stinking sense. What am I reading, some couples therapy book??
In real-life, you're not always going to hear sentences that you're used to and are comfortable with hearing. Duolingo is just preparing you for that.