The English equivalent of 'potest' is It is able. The person of the verb is the singular form of the third, which may be translated as 'he', 'she', or 'it'. The verb is the present indicative of 'possum, posse'.
This verb means "he is able".
"Let him not belong to another who can belong to himself."
Without some context, an absolute translation is not possible. Literally, it's: He (or she) can count.
"Someone who has been delegated cannot delegate," i.e., no sub-delegation is allowed.
Ecce Romani - Look, the Romans! 'Sextus can't sleep' - Sextus non potest dormire.
Dominus audire potest.
"It is pointless to do with more what can be done with less." One of the tenets of Occam's (or Ockhams's) razor.
What can be the pleasure of life when friendships are removed.
The sentence Qui potest capere capiat is Latin for "Let him who can take, take". It appears in the Latin (Vulgate) Bible at the end of Matthew 19:12, where it is translated "He that can take, let him take it" in the Douay translation, and "He who is able to receive this, let him receive it." in the Revised Standard Version.
"A thing is worth as much as it can be sold for."
Love can't be mixed with fear is the English equivalent of 'Amor misceri cum timore non potest'. In the word by word translation, the noun 'amor' means 'love'. The passive verb 'misceri' means 'to be mixed'. The preposition 'cum' means 'with'. The noun 'timore' means 'fear'. The adverb 'non' means 'not'. The verb 'potest' means '[it] is possible'.
Potest fieri ut modo sint tres.