its possible to break a clasp, but its also unlikely unless you are really yanking on it hard. the waist on these jeans will definitely stretch out, just be patient. my size 27 19cm were pretty tight in the waist at first, but now they are plenty loose. they were 14.5" in the waist when i got them and they are now 15.5", so they stretched 2 full sizes with about a month of wear.