The term 'Cause to Feel Sure' can be broken down into three crossword solutions: KNOW (4 letters), GRIEVE (6 letters), and AIL (3 letters). Knowing is an action that involves having a certain level of understanding or awareness of something. Grieving is an emotional response to a loss or disappointment, usually involving sadness and sorrow. Ailing is a state of being ill or unwell. Therefore, the term 'Cause to Feel Sure' can be interpreted as having knowledge, understanding, or awareness of something, which can help to alleviate grief and illness.