Situation : There is a girl who can't be together with her boyfriend because he is in army. And thinking of the moment that she has to let him go to army, can she say,
- That was the beginning of waiting for him.
- That was the onset of waiting for him.
Or are there any good expressions for the moment that someone start to wait for the other?
Those are grammatical utterances but not quite natural. A native speaker, in conversation, is not likely to choose either of those patterns, which use a noun phrase, but instead would treat waiting as a verb and say something like
That was when I started waiting for him.
That was when I began waiting for him.
That was when I began to wait for him.
Alternatively, the speaker would use the noun wait:
That was the beginning of my wait for him.
That was when my wait began.
In a story you might read:
That was when the waiting began.
especially if the theme of the story is her waiting for him in a number of ways, sometimes literally, sometimes figuratively, over the course of a long relationship.
