These characters combine powerfully. `信守 (xìnshǒu)` means to “keep with faith/sincerity.” `承诺 (chéngnuò)` means a “promise that has been undertaken.” Together, “信守承诺 (xìnshǒu chéngnuò)” literally means “to faithfully guard the promise you have undertaken.” This structure emphasizes both the sincerity of the promise and the dedicated action required to fulfill it.