This is the 3413th most frequent Russian word.
превращается
"Turns into" or "transforms."
Here, 'превращается' describes the process of transformation of 'water' into an 'ice' state.
Вода превращается в лёд, когда замерзает.
Water turns into ice when it freezes.
In this sentence, 'превращается' signifies the transition of a 'dream' metaphorically becoming 'reality'.
С детства её мечта превращается в реальность.
Since childhood, her dream turns into reality.
Here, 'превращается' is used to illustrate a biological transformation of 'a caterpillar' into 'a butterfly'.