Dreaming of applying mehandi is a good dream as per dream meaning and interpretation. It means that you will find love and there will be progress in romantic matters. If while putting mehandi it goes wrong or gets bad then it you can expect problems in an ongoing relationship. It also means problems in an already decided marriage.
Dreaming of someone else applying mehandi or you are putting it on someone else means that you are not in a good relationship and that you will be cheated.
Dream of all family members or friends applying mehandi together means there will happy occasions in the family including wedding.
Dream of you applying mehandi with children or friends is a sign of desire fulfillment including job or marriage with a desired partner.