Americans almost never use "shall". My understanding of British English is that "shall" is used to form future tense for first person (I/we), and "will" is used to form the future tense for second and third person (he/she/you/they). Then, to express commands, determination, or strong desire, you use "shall". So "You shall pay the rent" is a command or exhortation for you to do so, and "You will pay the rent" is a simple future tense statement of fact.
tldr; skal can mean both, depending on the meaning of "shall" or "will".