While there is no place for blind faith in Yoga, conviction plays a foundational role.
Sutra 1.20 | śraddha vīrya smṛti samādhi prajñā pūrvaka itareśām
Sutra 1.20 provides a general framework for practice for attaining higher levels of concentration (Samādhi). Śraddha here means clarity and conviction that arise after careful contemplation, observation, analysis and study. For example, the thoughts such as “this is the right thing to do”, “this is what it is”, “this is the worthy goal”, etc.
Such conviction then provides the necessary energy and stamina (Vīrya) to pursue one’s goals. Śraddha fuels Vīrya. Without a strong conviction about what one pursues, it is impossible to sustain the effort over long time. Vyāsa says Śraddha is like a loving mother, who would keep vigil over a child learning to walk and lovingly help the tottering child to get back on her feet. Śraddha helps the Yogi get back on track should he stumble.
Smṛti means memory or recollection. In the Yoga context, it is about constant recollection of the object of concentration.
This basic framework is universally applicable. It does not matter what you are after. If you are not really convinced about it, you are unlikely to sustain effort and if you do not constantly recollect your goal, you are likely to fall prey to distractions.