Одного взгляда на нее было достаточ

Одного взгляда на нее было достаточно, чтобы понять, что она очень устала.

Результаты (английский) 1:

One look at her was enough to realize that she is very tired.

Результаты (английский) 2:

One look at her was enough to understand that she was very tired.

Результаты (английский) 3:

one glance at her was enough to know that she is very tired.