18:64  

सर्वगुह्यतमं भूयः शृणु मे परमं वचः ।
इष्टोऽसि मे दृढमिति ततो वक्ष्यामि ते हितम् ॥१८- ६४॥

sarwaguhyatamaM bhooyaH shRRiNu me paramaM wachaH ।

iShTo'si me dRRiDhamiti tato wakShyaami te hitam ॥१८- ६४॥

Source: Automatic ITRANS Transliteration

Hear again from me the supreme declaration, [most] secret of all.
You are so strongly beloved to me that I speak in your interest.

Source: Milind S. Pandit

Hear again My supreme word, the most secret of all. You are very dear to Me, therefore, I shall tell this for your benefit.

Source: The Bhagavad-Gita: The Sacred Song

Because you are My very dear friend, I am speaking to you the most confidential part of knowledge. Hear this from Me, for it is for your benefit.

Source: Bhagavad Gita As It Is