«أَوْ تَضْمَنُوا لِي أَنْ لَا تَتَّخِذُونِي كَلًّا»
Or assure me that you will not treat me as a burden.
Taḍmanū lī asks for an assurance. The clause an lā tattakhidhūnī kallan uses subordinating an, a negative lā, and the verb ittakhadha with two complements: the speaker as the first object and “a burden” as the second.
Kallan is not another person; it is the characterization the hosts are asked to avoid applying to the guest. The grammar makes the interpersonal condition precise.