Stir all ingredients except the cornstarch in a saucepan. Mix the cornstarch with a small amount of the sauce in a small cup. Heat the rest of the sauce while stirring, then stir in the mixed maizena (cornstarch). Continue stirring for 1 minute.
Bring to the table warm or at room temperature.
The sauce can be prepared 1 week in advance, in which case refrigerate with the lid closed. Before use, heat slightly once more.
*Original: 90 ml of mango juice or nectar and 90 ml of fresh passion fruit juice.