I watched her become a mother vs I watched her becoming a mother [duplicate]
Which one has more correct way to put, and what are the differences found on those two sentences?
Both are correct. There is a (rather insignificant, though) difference in meaning.
I watched her become a mother = I remember her from before pregnancy, and I can see how she's different now. (The emphasis is on the difference).
I watched her becoming a mother = I remember the process of her changing from day to day. (The emphasis is on the transformation process).
See: https://dictionary.cambridge.org/pl/grammar/british-grammar/hear-see-etc-object-infinitive-or-ing