Albert Barnes Commentary Psalms 45:11

"So will the king desire thy beauty; For he is thy lord; and reverence thou him." — Psalms 45:11 (ASV)

So shall the king greatly desire thy beauty - That is, in consequence of your love to him and your entire devotion of yourself to him. The word “desire” here is equivalent to having pleasure in, meaning that his affection would thus be fixed on her. In this way—by forgetting her own home and devoting herself to him—she would secure his affection.

In the married life, mere “beauty” will not permanently secure the love of a husband. The heart, as given to him and as faithful to him, will alone secure his love.

Similarly, it is nothing but sincere affection—true love on the part of the professed friends of the Savior, the forgetting and forsaking of all else—that will secure his love or make the church to him an object of desire.

For he is thy Lord - That is, as a husband he sustains this relation to you, or this title may be given to him. In what sense this is true in respect to a husband, see the notes at (1 Peter 3:6) and (1 Corinthians 11:3). In respect to the Savior, the dominion implied in the word “Lord” is absolute and entire.

And worship thou him - That is, as applicable to a bride, show him respect, honor, reverence. See the notes at (Ephesians 5:33). The word properly means to bow down; then, to show respect as to a superior; and then, to show proper respect to God, namely, by worshipping or adoring him. See the notes at (Matthew 2:11); see also (Matthew 8:2), (Matthew 14:33), (Matthew 15:25), (Matthew 18:26), (Matthew 28:9), (Revelation 19:10), and (Revelation 22:9). Compare the notes at (Hebrews 1:6).