I do not profess to know exactly what Maya Angelou was trying to express through her quote, nor do I know the context in which she wrote it. I also confess to know nothing about her personal life, nor her religious convictions. However, if I were to take a guess about what her quote means, here is my interpretation of it and my concluding judgment.
I believe Maya was trying to express the truth that in order for a Christian man to truly gain the trust and acceptance of a woman's heart, he must first (in a sense) go through Jesus first, who is her Shepherd, Protector, and true Lord over her heart and life. In other words, the godly woman does not belong to anyone accept Jesus Christ. And in a spiritual sense, the pursuing man must first be given "permission" to take her hand rightfully and God-fearingly from Jesus Himself (I mean that figuratively, meaning the man himself must be "in Christ" first, just as the godly woman is). The human equivalent would be the old fashion way of a man asking the woman's father for her hand in marriage.
I could be wrong about this, but I believe the "hidden" part of the quote is being misunderstood. I view the "hidden" aspect as meaning the godly woman is living such a God-honoring life, that she if fully immersed in God's will (or being "in the heart of Christ"), and that it will actually show in her life, not be kept secret from those around her. For example in Psalm 119:11 the psalmist says to God, "I have hidden your word in my heart, that I might not sin against you." This verse is not promoting the idea of hiding God's Word from the public, but to so immerse your heart in it that it makes a direct change in your outward life and behavior. So too, I believe Maya is stating in this quote that a woman should be so immersed (or hidden) in Christ that it changes her countenance and behavior and thus raises the public's perception of what kind of man it would take to be genuinely acceptable for her as a true daughter of the King of Kings.
I believe the quote ultimately comes down to a woman being "conformed to the image of Christ" - Romans 8:29. If she is truly hidden in Christ, she will begin to resemble Him. And for a man to be unattracted to women who resemble Christ, would be akin to that man not being attracted to Jesus Himself, and therefore not be one a godly woman should allow into her own heart.
Like I said, I could be completely misunderstanding Maya's quote, but if my interpretation is correct, than I would gladly applaud all women who use this quote as a standard by which they judge which men will be allowed to gain access to their hearts - which is only through the heart of Christ.