Getting big returns from financial portfolios, whether through stocks, bonds, ETFs, other securities, or a combination of all, is an investor's dream. But for income investors, generating consistent cash flow from each of your liquid investments is your primary focus.While cash flow can come from bond interest or interest from other types of investments, income investors hone in on dividends. A dividend is that coveted distribution of a company's earnings paid out to shareholders, and investors often view it by its dividend yield, a metric that measures the dividend as a percent of the current stock price. Many academic studies show that dividends make up large portions of long-term returns, and in many cases, dividend contributions surpass one-third of total returns.Sun Life in FocusBased in Toronto, Sun Life (SLF) is in the Finance sector, and so far this year, shares have seen a price change of -6.5%. The financial services company is currently shelling out a dividend of $0.52 per share, with a dividend yield of 4%. This compares to the Insurance - Life Insurance industry's yield of 0.81% and the S&P 500's yield of 1.43%.Looking at dividend growth, the company's current annualized dividend of $2.08 is up 12.4% from last year. Over the last 5 years, Sun Life has increased its dividend 4 times on a year-over-year basis for an average annual increase of 7.82%. Future dividend growth will depend on earnings growth as well as payout ratio, which is the proportion of a company's annual earnings per share that it pays out as a dividend. Sun Life's current payout ratio is 44%. This means it paid out 44% of its trailing 12-month EPS as dividend.Earnings growth looks solid for SLF for this fiscal year. The Zacks Consensus Estimate for 2022 is $5.02 per share, which represents a year-over-year growth rate of 4.37%.Bottom LineInvestors like dividends for a variety of different reasons, from tax advantages and decreasing overall portfolio risk to considerably improving stock investing profits. However, not all companies offer a quarterly payout.High-growth firms or tech start-ups, for example, rarely provide their shareholders a dividend, while larger, more established companies that have more secure profits are often seen as the best dividend options. Income investors have to be mindful of the fact that high-yielding stocks tend to struggle during periods of rising interest rates. With that in mind, SLF is a compelling investment opportunity. Not only is it a strong dividend play, but the stock currently sits at a Zacks Rank of 3 (Hold). Infrastructure Stock Boom to Sweep America A massive push to rebuild the crumbling U.S. infrastructure will soon be underway. It’s bipartisan, urgent, and inevitable. Trillions will be spent. Fortunes will be made. The only question is “Will you get into the right stocks early when their growth potential is greatest?” Zacks has released a Special Report to help you do just that, and today it’s free. Discover 5 special companies that look to gain the most from construction and repair to roads, bridges, and buildings, plus cargo hauling and energy transformation on an almost unimaginable scale.Download FREE: How to Profit from Trillions on Spending for Infrastructure >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Sun Life Financial Inc. (SLF): Free Stock Analysis Report To read this article on Zacks.com click here.