We can usually tell when you’re in love with someone else — but how can anyone tell when you’re truly in love with G-d? There are ways. You’d be known to truly love G-d, to begin with, if you’re always caught “renouncing things … that distract you from (Him)”.
You’d also be known to love Him when “the look of fear and dread of G-d is on your face” all the time, we’re told. But don’t get thrown by that, though, and ask how “fearing” or “dreading” G-d would indicate that you love Him, because there are two sorts of fear when it comes to G-d: “the fear of punishment and tribulation”, which is a rather low and primitive one, and then there’s “revering His glory, exaltedness and might”, and it’s the highest level one could ever attain to, as well as “the most profound form of longing for Him” there is. It’s the latter that’s closely tied-in with truly adoring G-d (see the introduction to this gate).
There are many other signs of such love. One is “it being one and the same to you whether people praise or insult you for fulfilling G-d’s will”; another is your willingness to sacrifice everything in order to fulfill His wishes; another is “your having the name of G-d on your lips in praise, gratitude, and exultation all the time”; another “is your making everything you do or say … contingent upon G-d’s will”; another “is your guiding and instructing others in how to serve G-d”, which is so important because “if you only improve your own soul, your merits will be small, but if you improve your soul and the soul of others as well” you’d have done something momentous; another sign “is the fact that your (only) source of happiness and joy is the merits you’d have accrued” and the closeness to G- d that would result; and another “is your prostrating yourself at night in deep devotional prayer”, for after all, isn’t nighttime an occasion for “lovers to devote themselves to the one they love”?.
And, finally, a clear sign of your loving G-d “is your joy and glee in G-d Himself, in the knowledge of Him, in the longing to please Him, in your delight in His Torah, and in your affinity with all (others) who worship Him”.