In De L'Amour Stendhal suggests the concept of crystallization, which according to him is part of the process of being in love. Crystallization is, as Stendhal puts it, "a mental process which draws from everything that happens new proofs of the perfection of the loved one". I think Stendhal is right, that is, that everyone who has the experience of being in love has the experience of crystallization.
"Crystallization" seems to me, however, just a fancy term for the kind of confirmation bias that a lover has towards her beloved. A person has confirmation bias towards something that she wants to be the case when she selectively notices or focuses upon evidence that would support it while ignoring evidence that would confute it. A lover wants her beloved to be perfect, which is why she "draws from everything that happens new proofs of the perfection of the loved one", and is blind to whatever flaws her beloved has. When you call this confirmation bias, it sounds bad; but when you call it crystallization, it sounds romantic. As it is sometimes said, this is mere semantics.