“癞蛤蟆想吃天鹅肉”有没有相近的英语谚语?

1． aim at the moon 妄想,痴心妄想
A:I want to marry Sally,mammy.
B:Don’t aim at the moon.Sally is so excellent.It is impossible for her to marry you.
A:I am also outstanding.I have a lot of confidence.
A：妈妈,我想和萨莉结婚.
B：不要痴心妄想了,萨莉是那么优秀,要她嫁给你是不可能的.
A：我也很出色的.我充满自信.
beast and beauty 引申一下 beast want beauty