For me, this quote throws much light on the question of risk-taking Vs. caution in the navy.
I hadn't realized the full impact of Wentworth's risk-taking before- so his confidence and self-belief were more likely to make him another casualty of war ?
At this point in the book; for Anne to ignore Lady Russell's caution and keeping in mind Sir Walter professed resolution to do nothing for them; for Anne to accept Wentworth's proposal was asking her to accept a great risk at the start of his naval career.
I agree Capt. Wentworth's rise and fortune are testimony to his courageous, resourceful charecter. Yet it's impossible to forsee if risk-taking will be profitable or fatal.