Praise be to Allah.
There are a number of things that should be noted:
With regard to the dream that you have seen, you should ask people who have knowledge of that, whose religious commitment and ‘aqeedah you trust, so that they may explain its meaning to you. Beware of ignorant people and charlatans.
Many people think that following istikhaarah there has to be a dream or a feeling of ease in the heart, and so on, but that is not the case. Even if no such thing happens when a person has prayed istikhaarah and done his best to find out what is best for him, such as consulting people, examining the issue and asking those who have experience, then he goes ahead and does it, then it is hoped that this will be what is best for him, even if he does not feel at ease in his heart in the beginning. Even if we assume that he does not succeed in this matter that he goes ahead with after praying istikhaarah, it may be good for him even if he does not know it, but his Lord knows, may He be exalted.
Ibn al-Haaj al-Maaliki said:
Some of them pray istikhaarah as prescribed in sharee’ah and then wait until they see a dream from which they will decide whether they should go ahead and do whatever they prayed istikhaarah about or not, or until someone else sees a dream for them. This does not count for anything, because the infallible one (peace and blessings of Allaah be upon him) told us to pray istikhaarah and consult others, not to rely on what is seen in dreams. End quote
If we assume that the interpretation of the dream suggests something good, good dreams are no more than hints, but they cannot be relied on. Rather you should try to find out and ask about the one who has proposed marriage, make sure whether he is religiously committed and of good character, and other things that you should find out about him. If you are certain of these matters then the good dream is no more than a message to be of good cheer when proceeding.
We ask Allaah to make goodness easy for you, and to bless you.
And Allaah knows best.