श्री भगवानुवाच असंशयं महाबाहो मनो दुर्निग्रहं चलं। अभ्यासेन तु कौन्तेय वैराग्येण च गृह्यते ॥

asanśhayaṁ mahā-bāho mano durnigrahaṁ chalam abhyāsena tu kaunteya vairāgyeṇa cha gṛihyate

Without doubt, O mighty-armed, the mind is hard to curb and restless; but it may be curbed by constant practice and by dispassion.

In plain words: Krishna agrees that the mind is restless and hard to control. But he says it can be controlled through steady, repeated practice and by letting go of cravings.