que + un

(intransitive) to be one and the same, to be as one / (intransitive) to be one and the same, to be as one; (transitive with avec) to be at one with

(informal) and then some! and how!

there's a fine line between... (said of things that are very close to one another, such that one could easily lead to the other)

two heads are better than one

you only go around once, you only live once, YOLO

(figuratively) to be as good as one's word, to be true to one's word

two heads are better than one

better safe than sorry; a belt-and-braces/belt-and-suspenders approach always wins the day

doubly, so as to make sure, so that there be absolutely no doubt / absolutely! with pleasure! yes please!