With an electric mixer beat the cream cheese until it is smooth. Add the heavy cream and beat until the mixture starts to become whipped and fluffy like whipped cream.
Add in the milk and sweetened condensed milk and slowly blend until everything is fully incorporated.
To freeze, either add to an ice cream maker and freeze, or place into a gallon zipper bag and lay flat in the freezer. Every hour or so knead the bag with your hands making sure all frozen chunks are fully incorporated. Continue for about 4 hours or until frozen.
Guava Syrup
Add the guava juice to a small cup or bottle with a tight fitting lid. Add the corn starch and shake until fully dissolved.
Pour this mixture into a small sauce pan and heat over medium heat until the sauce begins to thicken. Let cool and serve over the cream cheese ice cream.