US businesses are brushing off those “Now Hiring” signs: Job openings rose sharply in April to their highest level in nearly two years, Bureau of Labor Statistics data showed Tuesday. However, the latest look at labor turnover also showed that those job postings aren’t necessarily turning into job offers – the US job market remains entrenched in a low-hire, low-fire dynamic. The number of available jobs jumped to an estimated 7.62 million positions at the end of April, increasing from 6.89 million in March and bucking a two-month decline, the latest Job Openings and Labor Turnover Survey showed. At the same time, the number of new hires and layoffs both tumbled after bolting higher in March; and voluntary quits fell to their lowest level in nearly six years, an indication of workers’ slipping confidence in the labor market.