अन्तकाले च मामेव स्मरन्मुक्त्वा कलेवरम्। यः प्रयाति स मद्भावं याति नास्त्यत्र संशयः ॥

anta-kāle cha mām eva smaran muktvā kalevaram yaḥ prayāti sa mad-bhāvaṁ yāti nāstyatra sanśhayaḥ

And he who, casting off the body, goeth forth thinking upon Me only at the time of the end, he entereth into My being: there is no doubt of that.

In plain words: Krishna says that anyone who thinks of him alone when they die goes to be one with him. There is no doubt about it.