The Guardian of Faith, The Giver of Faith, The Trustworthy, The Giver of Security, The One who fulfills promises.
From Allah alone comes faith and guidance. And so is He the ONLY rightful Guardian of it too. We see around us people who have had so much faith at one point of their lives, yet at another point of their lives, they are completely gone astray.
We also see people around us who have spent a great deal of their lives in sin, yet at certain point Allah guides them and fills their hearts with faith.
This name teaches and reminds us that, we needn't take our faith for granted but should entrust it with The One who is The Guardian of it, who is The Trustworthy, who does not ever break the trust His slaves put in Him, The One who never fails His promises and that is THE greatest security one can ever have