Realises is a verb that usually means to become fully aware of something or to understand the reality of it. However, there are plenty of other synonyms you can use instead of just "realises." Some similar phrases include "recognizes," "perceives," "acknowledges," "comprehends," "apprehends," and "grasps." Each of these alternative verbs has a slightly different connotation, but they all convey a sense of coming to understand something. It's important to consider which synonym fits best in a particular context to accurately convey the intended meaning. Using a range of synonyms can also help to avoid repetition and keep writing dynamic and engaging.