Mindrolling Jetsun Khandro Rinpoche has been talking to her students when they gather for programs via Skype. This is what she had to say at a program dedicated to Ngondro, aka "the Preliminary practices."
Practitioners must believe in the power of purification of karma. That’s why you are all intellect (?). If you didn’t believe it, there is no way you could having confidence in possibility of enlightenment.
Exertion on path – to be honest, whole-hearted. Very strong confidence in accomplishment stage of realization that becomes cause of liberations of all sentient beings. The full enlightenment, freedom from samsara for self and other.
Of all practices, ngondro emphasizes this most important. What kind of a result we all believe in. must encourage meditator- to have the power to hold the result in your hand – results in purification of karma and attainment of merit.