The word that best fits the description of the extract is promise. In this extract, the person is stating the intention to do something or conduct some activity. The person is doing it under a self-imposed oath. For example, the person uses the words such as:
And I’d promise myself that when I grew up and was strong, I’d follow that road, and it and I would find the sea together.
The person is stating his or her resolve to do something positive.
Answer: The line in the excerpt from Eugene O'Neill's "Beyond the Horizon" that reflects the idea of pursuing one's dreams is:
And I’d promise myself that when I grew up and was strong, I’d follow that road, and it and I would find the sea together. (With a smile) You see, my making this trip is only keeping that promise of long ago.