Swami Vivekananda himself saw God Pratyaksha i.e. face-to-face first in Savikalpa Samadhi during which he saw the living, talking, smiling Ma Kali.
And secondly during Nirvikalpa Samadhi when he directly experienced the Infinite Sat-Chit-Ananda Divine Consciousness, also known as Brahman or God the Absolute in Advaita Vedanta.
It is from this substrate of Consciousness that has sprung the entire Universe of matter & living beings.
So when Swami Vivekananda says that God can be seen face-to-face, he is speaking from personal experience. Swamiji and numerous Indian rishis have seen God & so can we!
The above video has been excerpted from: Does Hinduism Deserve to be Called the Sanatan Dharma? Swami Vivekananda’s Powerful Answer