Never- At no time in the past or future ( कभी नहीं)

Ever- At any time in the past or future (कभी)

As per the definition above, never is negative and ever is positive. Let’s see some examples.

I have never been to Delhi (मैं कभी दिल्ली नहीं गया हूँ)
Has it ever happened? (क्या ये कभी हुआ है?)
Have you ever been to Delhi? (क्या आप कभी दिल्ली गये हैं?)
I have never seen a ghost (मैने भूत को कभी नहीं देखा है)
Will he ever become a good human being? (क्या वो कभी अच्छा इनसान बनेगा?)
Has Chris Gayle ever spared any bowler?(क्या क्रिश गेल ने किसी गेंदबाज़ को कभी छोड़ा है?