Sometimes 'Sale' needs a bit more room in different languages. This css snippet should help.
It can go in Theme Options > Custom Code.
.onsale-wrap .onsale-inner .onsale {
line-height: 1.3em !important;
}
.onsale-wrap .onsale-inner {
width: 56px;
height: 56px;
}
.onsale-wrap {
width: 62px;
}
.single-product-details .onsale-wrap .onsale-inner .onsale {
line-height: 1.3em;
}
.single-product-details .onsale-wrap {
width: 82px;
}
.single-product-details .onsale-wrap .onsale-inner {
width: 76px;
height: 76px;
}