Recinto (Spanish for “enclosure” or “facility”) comes from the Latin re- (which just adds emphasis) and the Latin cintus (a noun meaning “surrounding” — in the literal sense, of something that surrounds something else, like enclosing a circle around them; or similarly, “encircling.”)
From that same root, we get the English word precinct — which makes sense, since a precinct is really just a radius or… encircling to define a neighborhood.
More surprisingly from same root is, cinch. This Latin word meaning a circling came to mean sword-belt (it is a belt that encriclces you!), which then came to mean the Spanish cincha, meaning “girdle.” That then came back to English to mean, “a sure thing” and then “easy” — because your girdle stays on tightly to be a sure thing. It is a cinch!
1859, American English, “saddle-girth,” from Spanish cincha “girdle,” from Latin cingulum “a girdle, a swordbelt,” from cingere “to surround, encircle,” from PIE root *kenk- (1) “to gird, encircle” (cognates: Sanskrit kankate “binds,” kanci “girdle;” Lithuanian kinkau “to harness horses”). Replaced earlier surcingle. Sense of “an easy thing” is 1898, via notion of “a sure hold” (1888).
We can see the c‑n-t root clearly in recinto and precinct, and the very similar c‑n-ch in cinch as well.
The Spanish creer, “to believe”, is easy to remember once we realize it comes from the same root as… incredible. Both are from the Latin credibilis (meaning “worth of believing”), and the in- prefix is a negation, so that which is incredible is literally… unbelievable. And thus creer is also a first cousin to being… credible. Ahhh!
The Spanish martillo (“hammer”) comes from the Latin malleus meaning the same. And from this Latin root malleus we get the English… malleable. So something that is malleable, changeable, is figuratively… hammerable.
We see that the Spanish m‑rt-ll maps to the English m‑ll.
Enviar (Spanish for “To send”) comes from the Latin for the same, inviare. From that same root, we get the English… envoy. An envoy just sends a message, after all!
The e‑n-v root is self-evident in both words. And the Latin inviare comes from the root via for “road”, from which we get endless English words, including… via!
The Spanish ladrón, for thief, sounds unrelated to any English word.
But, it does have an interesting connection to the English for the same, Burglar.
Burglar comes from the Latin burgus, which meant “castle” or a “fortified town” — think about the ‑burg ending in many place names, like Pittsburgh or Edinborough.
But, if burglar comes from burgus, then where did the ‑l- in the middle come from?
Well, the ‑l- was inserted slowly over time under the influence of the Latin for thief, latro. The word for “thief” was, unconsciously, made to sound similar to the other word for thief! And from latro we get, directly, the Spanish ladrón.
Thus, although burglar isn’t directly descended from ladrón, they are incestuous cousins.