Fire with air
Air keeps fire going. Libra pays attention, asks the question that lets Leo talk, and adjusts to what Leo wants without being asked twice. Leo, in return, provides the certainty Libra habitually lacks, which is genuinely restful for a sign that weighs everything.
The trouble in the exchange is that Libra accommodates automatically, and Leo does not always notice it is happening. A pattern establishes itself in which one person's preferences quietly become the plan, and neither party consciously chose it.
Fixed and cardinal
Libra opens and Leo holds. Libra proposes the trip, the dinner, the change of arrangement; Leo either takes it up wholeheartedly or does not move at all.
The modality friction shows in negotiation. Libra's method is to keep options open so a settlement can be found. Leo's method is to state a preference and expect it honoured. Libra reads Leo as inflexible and Leo reads Libra as having no preferences to honour, which is not what Libra means by keeping the peace.
The Sun and Venus
Leo is ruled by the Sun and Libra by Venus, which is a mild and sociable combination by the standards of the rulership scheme. Neither body is associated with severity, and the pairing tends to be pleasant to be around for that reason.
What neither ruler supplies is any appetite for conflict or for unglamorous practical work. Whether the two charts contain those qualities elsewhere is the useful question, and it is not answerable from the sun signs.
Where it grinds
Resentment without an argument. Libra concedes to keep things smooth and then holds the concession against Leo, who was never told a concession was being made. This accumulates slowly and surfaces at an unrelated moment.
The second grind is attention outside the relationship. Libra is charming with everyone as a matter of habit rather than intent, and Leo, which reads attention as currency, notices where it is being spent. The complaint is rarely about anything specific, which makes it hard to settle.
A third strain shows up around money and effort. Both signs will spend on the occasion and neither is drawn to the dull maintenance that keeps a household running, so those tasks tend to fall to whoever minds the mess first.
What actually decides it
Not the suns. A sun sign covers everyone born within the same few weeks, so this page describes a tendency across a large group rather than the two people reading it.
The Moons determine whether daily life together is easy or effortful. Venus determines whether affection is expressed recognisably, and it rules half of this pairing already. Mars determines whether the avoided disagreements ever surface. Those four bodies tell you far more than two suns.
Questions people ask about this
Do Leo and Libra get on socially?
Generally yes. Both care about occasion and neither finds company draining, which makes the pairing pleasant in public.
What is the main risk?
Unspoken concession. Libra accommodates without saying so and then resents an arrangement Leo believed was mutual.
Does Venus ruling Libra make it easy?
It makes it agreeable. It does not supply appetite for conflict or for the practical work neither sign enjoys.
What should I compare beyond sun signs?
Moon, Venus and Mars in both charts. Mars matters most here because it governs the arguments this pairing avoids having.