Krishna does not agree to award devotional service to merely anyone. Krishna can easily offer a person material happiness or even liberation, but He does not agree very easily to award a person engagement in his devotional service. Devotional service can in fact be attained only through the mercy of a pure devotee. — The Nectar of Devotion, Page 14.
Always engage in devotional service with determination.
The real result of devotional service is the awakening of pure love for the Supreme Personality of Godhead, which continues under all circumstances.
Srimad Bhagavatam 5.24.19,
The child cries to have toys, but one who can cry for the Lord in love is certainly successful in the line of devotional service.